jdk-sandbox: comparison jdk/src/java.base/share/classes/java/lang/ClassLoader.java

equal deleted inserted replaced

-:836adbf7a2cd
+:3317bb8137f4
+/*
+* Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
+* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+*
+* This code is free software; you can redistribute it and/or modify it
+* under the terms of the GNU General Public License version 2 only, as
+* published by the Free Software Foundation.  Oracle designates this
+* particular file as subject to the "Classpath" exception as provided
+* by Oracle in the LICENSE file that accompanied this code.
+*
+* This code is distributed in the hope that it will be useful, but WITHOUT
+* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+* version 2 for more details (a copy is included in the LICENSE file that
+* accompanied this code).
+*
+* You should have received a copy of the GNU General Public License version
+* 2 along with this work; if not, write to the Free Software Foundation,
+* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+*
+* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+* or visit www.oracle.com if you need additional information or have any
+* questions.
+*/
+package java.lang;
+import java.io.InputStream;
+import java.io.IOException;
+import java.io.File;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.security.AccessController;
+import java.security.AccessControlContext;
+import java.security.CodeSource;
+import java.security.Policy;
+import java.security.PrivilegedAction;
+import java.security.PrivilegedActionException;
+import java.security.PrivilegedExceptionAction;
+import java.security.ProtectionDomain;
+import java.security.cert.Certificate;
+import java.util.Collections;
+import java.util.Enumeration;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.Stack;
+import java.util.Map;
+import java.util.Vector;
+import java.util.Hashtable;
+import java.util.WeakHashMap;
+import java.util.concurrent.ConcurrentHashMap;
+import sun.misc.CompoundEnumeration;
+import sun.misc.Resource;
+import sun.misc.URLClassPath;
+import sun.misc.VM;
+import sun.reflect.CallerSensitive;
+import sun.reflect.Reflection;
+import sun.reflect.misc.ReflectUtil;
+import sun.security.util.SecurityConstants;
+/**
+* A class loader is an object that is responsible for loading classes. The
+* class <tt>ClassLoader</tt> is an abstract class.  Given the <a
+* href="#name">binary name</a> of a class, a class loader should attempt to
+* locate or generate data that constitutes a definition for the class.  A
+* typical strategy is to transform the name into a file name and then read a
+* "class file" of that name from a file system.
+*
+* <p> Every {@link Class <tt>Class</tt>} object contains a {@link
+* Class#getClassLoader() reference} to the <tt>ClassLoader</tt> that defined
+* it.
+*
+* <p> <tt>Class</tt> objects for array classes are not created by class
+* loaders, but are created automatically as required by the Java runtime.
+* The class loader for an array class, as returned by {@link
+* Class#getClassLoader()} is the same as the class loader for its element
+* type; if the element type is a primitive type, then the array class has no
+* class loader.
+*
+* <p> Applications implement subclasses of <tt>ClassLoader</tt> in order to
+* extend the manner in which the Java virtual machine dynamically loads
+* classes.
+*
+* <p> Class loaders may typically be used by security managers to indicate
+* security domains.
+*
+* <p> The <tt>ClassLoader</tt> class uses a delegation model to search for
+* classes and resources.  Each instance of <tt>ClassLoader</tt> has an
+* associated parent class loader.  When requested to find a class or
+* resource, a <tt>ClassLoader</tt> instance will delegate the search for the
+* class or resource to its parent class loader before attempting to find the
+* class or resource itself.  The virtual machine's built-in class loader,
+* called the "bootstrap class loader", does not itself have a parent but may
+* serve as the parent of a <tt>ClassLoader</tt> instance.
+*
+* <p> Class loaders that support concurrent loading of classes are known as
+* <em>parallel capable</em> class loaders and are required to register
+* themselves at their class initialization time by invoking the
+* {@link
+* #registerAsParallelCapable <tt>ClassLoader.registerAsParallelCapable</tt>}
+* method. Note that the <tt>ClassLoader</tt> class is registered as parallel
+* capable by default. However, its subclasses still need to register themselves
+* if they are parallel capable. <br>
+* In environments in which the delegation model is not strictly
+* hierarchical, class loaders need to be parallel capable, otherwise class
+* loading can lead to deadlocks because the loader lock is held for the
+* duration of the class loading process (see {@link #loadClass
+* <tt>loadClass</tt>} methods).
+*
+* <p> Normally, the Java virtual machine loads classes from the local file
+* system in a platform-dependent manner.  For example, on UNIX systems, the
+* virtual machine loads classes from the directory defined by the
+* <tt>CLASSPATH</tt> environment variable.
+*
+* <p> However, some classes may not originate from a file; they may originate
+* from other sources, such as the network, or they could be constructed by an
+* application.  The method {@link #defineClass(String, byte[], int, int)
+* <tt>defineClass</tt>} converts an array of bytes into an instance of class
+* <tt>Class</tt>. Instances of this newly defined class can be created using
+* {@link Class#newInstance <tt>Class.newInstance</tt>}.
+*
+* <p> The methods and constructors of objects created by a class loader may
+* reference other classes.  To determine the class(es) referred to, the Java
+* virtual machine invokes the {@link #loadClass <tt>loadClass</tt>} method of
+* the class loader that originally created the class.
+*
+* <p> For example, an application could create a network class loader to
+* download class files from a server.  Sample code might look like:
+*
+* <blockquote><pre>
+*   ClassLoader loader&nbsp;= new NetworkClassLoader(host,&nbsp;port);
+*   Object main&nbsp;= loader.loadClass("Main", true).newInstance();
+*       &nbsp;.&nbsp;.&nbsp;.
+* </pre></blockquote>
+*
+* <p> The network class loader subclass must define the methods {@link
+* #findClass <tt>findClass</tt>} and <tt>loadClassData</tt> to load a class
+* from the network.  Once it has downloaded the bytes that make up the class,
+* it should use the method {@link #defineClass <tt>defineClass</tt>} to
+* create a class instance.  A sample implementation is:
+*
+* <blockquote><pre>
+*     class NetworkClassLoader extends ClassLoader {
+*         String host;
+*         int port;
+*
+*         public Class findClass(String name) {
+*             byte[] b = loadClassData(name);
+*             return defineClass(name, b, 0, b.length);
+*         }
+*
+*         private byte[] loadClassData(String name) {
+*             // load the class data from the connection
+*             &nbsp;.&nbsp;.&nbsp;.
+*         }
+*     }
+* </pre></blockquote>
+*
+* <h3> <a name="name">Binary names</a> </h3>
+*
+* <p> Any class name provided as a {@link String} parameter to methods in
+* <tt>ClassLoader</tt> must be a binary name as defined by
+* <cite>The Java&trade; Language Specification</cite>.
+*
+* <p> Examples of valid class names include:
+* <blockquote><pre>
+*   "java.lang.String"
+*   "javax.swing.JSpinner$DefaultEditor"
+*   "java.security.KeyStore$Builder$FileBuilder$1"
+*   "java.net.URLClassLoader$3$1"
+* </pre></blockquote>
+*
+* {@code Class} objects for array classes are not created by {@code ClassLoader};
+* use the {@link Class#forName} method instead.
+*
+* @jls 13.1 The Form of a Binary
+* @see      #resolveClass(Class)
+* @since 1.0
+*/
+public abstract class ClassLoader {
+private static native void registerNatives();
+static {
+registerNatives();
+}
+// The parent class loader for delegation
+// Note: VM hardcoded the offset of this field, thus all new fields
+// must be added *after* it.
+private final ClassLoader parent;
+/**
+* Encapsulates the set of parallel capable loader types.
+*/
+private static class ParallelLoaders {
+private ParallelLoaders() {}
+// the set of parallel capable loader types
+private static final Set<Class<? extends ClassLoader>> loaderTypes =
+Collections.newSetFromMap(new WeakHashMap<>());
+static {
+synchronized (loaderTypes) { loaderTypes.add(ClassLoader.class); }
+}
+/**
+* Registers the given class loader type as parallel capabale.
+* Returns {@code true} is successfully registered; {@code false} if
+* loader's super class is not registered.
+*/
+static boolean register(Class<? extends ClassLoader> c) {
+synchronized (loaderTypes) {
+if (loaderTypes.contains(c.getSuperclass())) {
+// register the class loader as parallel capable
+// if and only if all of its super classes are.
+// Note: given current classloading sequence, if
+// the immediate super class is parallel capable,
+// all the super classes higher up must be too.
+loaderTypes.add(c);
+return true;
+} else {
+return false;
+}
+}
+}
+/**
+* Returns {@code true} if the given class loader type is
+* registered as parallel capable.
+*/
+static boolean isRegistered(Class<? extends ClassLoader> c) {
+synchronized (loaderTypes) {
+return loaderTypes.contains(c);
+}
+}
+}
+// Maps class name to the corresponding lock object when the current
+// class loader is parallel capable.
+// Note: VM also uses this field to decide if the current class loader
+// is parallel capable and the appropriate lock object for class loading.
+private final ConcurrentHashMap<String, Object> parallelLockMap;
+// Hashtable that maps packages to certs
+private final Map <String, Certificate[]> package2certs;
+// Shared among all packages with unsigned classes
+private static final Certificate[] nocerts = new Certificate[0];
+// The classes loaded by this class loader. The only purpose of this table
+// is to keep the classes from being GC'ed until the loader is GC'ed.
+private final Vector<Class<?>> classes = new Vector<>();
+// The "default" domain. Set as the default ProtectionDomain on newly
+// created classes.
+private final ProtectionDomain defaultDomain =
+new ProtectionDomain(new CodeSource(null, (Certificate[]) null),
+null, this, null);
+// The initiating protection domains for all classes loaded by this loader
+private final Set<ProtectionDomain> domains;
+// Invoked by the VM to record every loaded class with this loader.
+void addClass(Class<?> c) {
+classes.addElement(c);
+}
+// The packages defined in this class loader.  Each package name is mapped
+// to its corresponding Package object.
+// @GuardedBy("itself")
+private final HashMap<String, Package> packages = new HashMap<>();
+private static Void checkCreateClassLoader() {
+SecurityManager security = System.getSecurityManager();
+if (security != null) {
+security.checkCreateClassLoader();
+}
+return null;
+}
+private ClassLoader(Void unused, ClassLoader parent) {
+this.parent = parent;
+if (ParallelLoaders.isRegistered(this.getClass())) {
+parallelLockMap = new ConcurrentHashMap<>();
+package2certs = new ConcurrentHashMap<>();
+domains = Collections.synchronizedSet(new HashSet<>());
+assertionLock = new Object();
+} else {
+// no finer-grained lock; lock on the classloader instance
+parallelLockMap = null;
+package2certs = new Hashtable<>();
+domains = new HashSet<>();
+assertionLock = this;
+}
+}
+/**
+* Creates a new class loader using the specified parent class loader for
+* delegation.
+*
+* <p> If there is a security manager, its {@link
+* SecurityManager#checkCreateClassLoader()
+* <tt>checkCreateClassLoader</tt>} method is invoked.  This may result in
+* a security exception.  </p>
+*
+* @param  parent
+*         The parent class loader
+*
+* @throws  SecurityException
+*          If a security manager exists and its
+*          <tt>checkCreateClassLoader</tt> method doesn't allow creation
+*          of a new class loader.
+*
+* @since  1.2
+*/
+protected ClassLoader(ClassLoader parent) {
+this(checkCreateClassLoader(), parent);
+}
+/**
+* Creates a new class loader using the <tt>ClassLoader</tt> returned by
+* the method {@link #getSystemClassLoader()
+* <tt>getSystemClassLoader()</tt>} as the parent class loader.
+*
+* <p> If there is a security manager, its {@link
+* SecurityManager#checkCreateClassLoader()
+* <tt>checkCreateClassLoader</tt>} method is invoked.  This may result in
+* a security exception.  </p>
+*
+* @throws  SecurityException
+*          If a security manager exists and its
+*          <tt>checkCreateClassLoader</tt> method doesn't allow creation
+*          of a new class loader.
+*/
+protected ClassLoader() {
+this(checkCreateClassLoader(), getSystemClassLoader());
+}
+// -- Class --
+/**
+* Loads the class with the specified <a href="#name">binary name</a>.
+* This method searches for classes in the same manner as the {@link
+* #loadClass(String, boolean)} method.  It is invoked by the Java virtual
+* machine to resolve class references.  Invoking this method is equivalent
+* to invoking {@link #loadClass(String, boolean) <tt>loadClass(name,
+* false)</tt>}.
+*
+* @param  name
+*         The <a href="#name">binary name</a> of the class
+*
+* @return  The resulting <tt>Class</tt> object
+*
+* @throws  ClassNotFoundException
+*          If the class was not found
+*/
+public Class<?> loadClass(String name) throws ClassNotFoundException {
+return loadClass(name, false);
+}
+/**
+* Loads the class with the specified <a href="#name">binary name</a>.  The
+* default implementation of this method searches for classes in the
+* following order:
+*
+* <ol>
+*
+*   <li><p> Invoke {@link #findLoadedClass(String)} to check if the class
+*   has already been loaded.  </p></li>
+*
+*   <li><p> Invoke the {@link #loadClass(String) <tt>loadClass</tt>} method
+*   on the parent class loader.  If the parent is <tt>null</tt> the class
+*   loader built-in to the virtual machine is used, instead.  </p></li>
+*
+*   <li><p> Invoke the {@link #findClass(String)} method to find the
+*   class.  </p></li>
+*
+* </ol>
+*
+* <p> If the class was found using the above steps, and the
+* <tt>resolve</tt> flag is true, this method will then invoke the {@link
+* #resolveClass(Class)} method on the resulting <tt>Class</tt> object.
+*
+* <p> Subclasses of <tt>ClassLoader</tt> are encouraged to override {@link
+* #findClass(String)}, rather than this method.  </p>
+*
+* <p> Unless overridden, this method synchronizes on the result of
+* {@link #getClassLoadingLock <tt>getClassLoadingLock</tt>} method
+* during the entire class loading process.
+*
+* @param  name
+*         The <a href="#name">binary name</a> of the class
+*
+* @param  resolve
+*         If <tt>true</tt> then resolve the class
+*
+* @return  The resulting <tt>Class</tt> object
+*
+* @throws  ClassNotFoundException
+*          If the class could not be found
+*/
+protected Class<?> loadClass(String name, boolean resolve)
+throws ClassNotFoundException
+{
+synchronized (getClassLoadingLock(name)) {
+// First, check if the class has already been loaded
+Class<?> c = findLoadedClass(name);
+if (c == null) {
+long t0 = System.nanoTime();
+try {
+if (parent != null) {
+c = parent.loadClass(name, false);
+} else {
+c = findBootstrapClassOrNull(name);
+}
+} catch (ClassNotFoundException e) {
+// ClassNotFoundException thrown if class not found
+// from the non-null parent class loader
+}
+if (c == null) {
+// If still not found, then invoke findClass in order
+// to find the class.
+long t1 = System.nanoTime();
+c = findClass(name);
+// this is the defining class loader; record the stats
+sun.misc.PerfCounter.getParentDelegationTime().addTime(t1 - t0);
+sun.misc.PerfCounter.getFindClassTime().addElapsedTimeFrom(t1);
+sun.misc.PerfCounter.getFindClasses().increment();
+}
+}
+if (resolve) {
+resolveClass(c);
+}
+return c;
+}
+}
+/**
+* Returns the lock object for class loading operations.
+* For backward compatibility, the default implementation of this method
+* behaves as follows. If this ClassLoader object is registered as
+* parallel capable, the method returns a dedicated object associated
+* with the specified class name. Otherwise, the method returns this
+* ClassLoader object.
+*
+* @param  className
+*         The name of the to-be-loaded class
+*
+* @return the lock for class loading operations
+*
+* @throws NullPointerException
+*         If registered as parallel capable and <tt>className</tt> is null
+*
+* @see #loadClass(String, boolean)
+*
+* @since  1.7
+*/
+protected Object getClassLoadingLock(String className) {
+Object lock = this;
+if (parallelLockMap != null) {
+Object newLock = new Object();
+lock = parallelLockMap.putIfAbsent(className, newLock);
+if (lock == null) {
+lock = newLock;
+}
+}
+return lock;
+}
+// This method is invoked by the virtual machine to load a class.
+private Class<?> loadClassInternal(String name)
+throws ClassNotFoundException
+{
+// For backward compatibility, explicitly lock on 'this' when
+// the current class loader is not parallel capable.
+if (parallelLockMap == null) {
+synchronized (this) {
+return loadClass(name);
+}
+} else {
+return loadClass(name);
+}
+}
+// Invoked by the VM after loading class with this loader.
+private void checkPackageAccess(Class<?> cls, ProtectionDomain pd) {
+final SecurityManager sm = System.getSecurityManager();
+if (sm != null) {
+if (ReflectUtil.isNonPublicProxyClass(cls)) {
+for (Class<?> intf: cls.getInterfaces()) {
+checkPackageAccess(intf, pd);
+}
+return;
+}
+final String name = cls.getName();
+final int i = name.lastIndexOf('.');
+if (i != -1) {
+AccessController.doPrivileged(new PrivilegedAction<Void>() {
+public Void run() {
+sm.checkPackageAccess(name.substring(0, i));
+return null;
+}
+}, new AccessControlContext(new ProtectionDomain[] {pd}));
+}
+}
+domains.add(pd);
+}
+/**
+* Finds the class with the specified <a href="#name">binary name</a>.
+* This method should be overridden by class loader implementations that
+* follow the delegation model for loading classes, and will be invoked by
+* the {@link #loadClass <tt>loadClass</tt>} method after checking the
+* parent class loader for the requested class.  The default implementation
+* throws a <tt>ClassNotFoundException</tt>.
+*
+* @param  name
+*         The <a href="#name">binary name</a> of the class
+*
+* @return  The resulting <tt>Class</tt> object
+*
+* @throws  ClassNotFoundException
+*          If the class could not be found
+*
+* @since  1.2
+*/
+protected Class<?> findClass(String name) throws ClassNotFoundException {
+throw new ClassNotFoundException(name);
+}
+/**
+* Converts an array of bytes into an instance of class <tt>Class</tt>.
+* Before the <tt>Class</tt> can be used it must be resolved.  This method
+* is deprecated in favor of the version that takes a <a
+* href="#name">binary name</a> as its first argument, and is more secure.
+*
+* @param  b
+*         The bytes that make up the class data.  The bytes in positions
+*         <tt>off</tt> through <tt>off+len-1</tt> should have the format
+*         of a valid class file as defined by
+*         <cite>The Java&trade; Virtual Machine Specification</cite>.
+*
+* @param  off
+*         The start offset in <tt>b</tt> of the class data
+*
+* @param  len
+*         The length of the class data
+*
+* @return  The <tt>Class</tt> object that was created from the specified
+*          class data
+*
+* @throws  ClassFormatError
+*          If the data did not contain a valid class
+*
+* @throws  IndexOutOfBoundsException
+*          If either <tt>off</tt> or <tt>len</tt> is negative, or if
+*          <tt>off+len</tt> is greater than <tt>b.length</tt>.
+*
+* @throws  SecurityException
+*          If an attempt is made to add this class to a package that
+*          contains classes that were signed by a different set of
+*          certificates than this class, or if an attempt is made
+*          to define a class in a package with a fully-qualified name
+*          that starts with "{@code java.}".
+*
+* @see  #loadClass(String, boolean)
+* @see  #resolveClass(Class)
+*
+* @deprecated  Replaced by {@link #defineClass(String, byte[], int, int)
+* defineClass(String, byte[], int, int)}
+*/
+@Deprecated
+protected final Class<?> defineClass(byte[] b, int off, int len)
+throws ClassFormatError
+{
+return defineClass(null, b, off, len, null);
+}
+/**
+* Converts an array of bytes into an instance of class <tt>Class</tt>.
+* Before the <tt>Class</tt> can be used it must be resolved.
+*
+* <p> This method assigns a default {@link java.security.ProtectionDomain
+* <tt>ProtectionDomain</tt>} to the newly defined class.  The
+* <tt>ProtectionDomain</tt> is effectively granted the same set of
+* permissions returned when {@link
+* java.security.Policy#getPermissions(java.security.CodeSource)
+* <tt>Policy.getPolicy().getPermissions(new CodeSource(null, null))</tt>}
+* is invoked.  The default domain is created on the first invocation of
+* {@link #defineClass(String, byte[], int, int) <tt>defineClass</tt>},
+* and re-used on subsequent invocations.
+*
+* <p> To assign a specific <tt>ProtectionDomain</tt> to the class, use
+* the {@link #defineClass(String, byte[], int, int,
+* java.security.ProtectionDomain) <tt>defineClass</tt>} method that takes a
+* <tt>ProtectionDomain</tt> as one of its arguments.  </p>
+*
+* @param  name
+*         The expected <a href="#name">binary name</a> of the class, or
+*         <tt>null</tt> if not known
+*
+* @param  b
+*         The bytes that make up the class data.  The bytes in positions
+*         <tt>off</tt> through <tt>off+len-1</tt> should have the format
+*         of a valid class file as defined by
+*         <cite>The Java&trade; Virtual Machine Specification</cite>.
+*
+* @param  off
+*         The start offset in <tt>b</tt> of the class data
+*
+* @param  len
+*         The length of the class data
+*
+* @return  The <tt>Class</tt> object that was created from the specified
+*          class data.
+*
+* @throws  ClassFormatError
+*          If the data did not contain a valid class
+*
+* @throws  IndexOutOfBoundsException
+*          If either <tt>off</tt> or <tt>len</tt> is negative, or if
+*          <tt>off+len</tt> is greater than <tt>b.length</tt>.
+*
+* @throws  SecurityException
+*          If an attempt is made to add this class to a package that
+*          contains classes that were signed by a different set of
+*          certificates than this class (which is unsigned), or if
+*          <tt>name</tt> begins with "<tt>java.</tt>".
+*
+* @see  #loadClass(String, boolean)
+* @see  #resolveClass(Class)
+* @see  java.security.CodeSource
+* @see  java.security.SecureClassLoader
+*
+* @since  1.1
+*/
+protected final Class<?> defineClass(String name, byte[] b, int off, int len)
+throws ClassFormatError
+{
+return defineClass(name, b, off, len, null);
+}
+/* Determine protection domain, and check that:
+- not define java.* class,
+- signer of this class matches signers for the rest of the classes in
+package.
+*/
+private ProtectionDomain preDefineClass(String name,
+ProtectionDomain pd)
+{
+if (!checkName(name))
+throw new NoClassDefFoundError("IllegalName: " + name);
+if ((name != null) && name.startsWith("java.")) {
+throw new SecurityException
+("Prohibited package name: " +
+name.substring(0, name.lastIndexOf('.')));
+}
+if (pd == null) {
+pd = defaultDomain;
+}
+if (name != null) checkCerts(name, pd.getCodeSource());
+return pd;
+}
+private String defineClassSourceLocation(ProtectionDomain pd)
+{
+CodeSource cs = pd.getCodeSource();
+String source = null;
+if (cs != null && cs.getLocation() != null) {
+source = cs.getLocation().toString();
+}
+return source;
+}
+private void postDefineClass(Class<?> c, ProtectionDomain pd)
+{
+if (pd.getCodeSource() != null) {
+Certificate certs[] = pd.getCodeSource().getCertificates();
+if (certs != null)
+setSigners(c, certs);
+}
+}
+/**
+* Converts an array of bytes into an instance of class <tt>Class</tt>,
+* with an optional <tt>ProtectionDomain</tt>.  If the domain is
+* <tt>null</tt>, then a default domain will be assigned to the class as
+* specified in the documentation for {@link #defineClass(String, byte[],
+* int, int)}.  Before the class can be used it must be resolved.
+*
+* <p> The first class defined in a package determines the exact set of
+* certificates that all subsequent classes defined in that package must
+* contain.  The set of certificates for a class is obtained from the
+* {@link java.security.CodeSource <tt>CodeSource</tt>} within the
+* <tt>ProtectionDomain</tt> of the class.  Any classes added to that
+* package must contain the same set of certificates or a
+* <tt>SecurityException</tt> will be thrown.  Note that if
+* <tt>name</tt> is <tt>null</tt>, this check is not performed.
+* You should always pass in the <a href="#name">binary name</a> of the
+* class you are defining as well as the bytes.  This ensures that the
+* class you are defining is indeed the class you think it is.
+*
+* <p> The specified <tt>name</tt> cannot begin with "<tt>java.</tt>", since
+* all classes in the "<tt>java.*</tt> packages can only be defined by the
+* bootstrap class loader.  If <tt>name</tt> is not <tt>null</tt>, it
+* must be equal to the <a href="#name">binary name</a> of the class
+* specified by the byte array "<tt>b</tt>", otherwise a {@link
+* NoClassDefFoundError <tt>NoClassDefFoundError</tt>} will be thrown. </p>
+*
+* @param  name
+*         The expected <a href="#name">binary name</a> of the class, or
+*         <tt>null</tt> if not known
+*
+* @param  b
+*         The bytes that make up the class data. The bytes in positions
+*         <tt>off</tt> through <tt>off+len-1</tt> should have the format
+*         of a valid class file as defined by
+*         <cite>The Java&trade; Virtual Machine Specification</cite>.
+*
+* @param  off
+*         The start offset in <tt>b</tt> of the class data
+*
+* @param  len
+*         The length of the class data
+*
+* @param  protectionDomain
+*         The ProtectionDomain of the class
+*
+* @return  The <tt>Class</tt> object created from the data,
+*          and optional <tt>ProtectionDomain</tt>.
+*
+* @throws  ClassFormatError
+*          If the data did not contain a valid class
+*
+* @throws  NoClassDefFoundError
+*          If <tt>name</tt> is not equal to the <a href="#name">binary
+*          name</a> of the class specified by <tt>b</tt>
+*
+* @throws  IndexOutOfBoundsException
+*          If either <tt>off</tt> or <tt>len</tt> is negative, or if
+*          <tt>off+len</tt> is greater than <tt>b.length</tt>.
+*
+* @throws  SecurityException
+*          If an attempt is made to add this class to a package that
+*          contains classes that were signed by a different set of
+*          certificates than this class, or if <tt>name</tt> begins with
+*          "<tt>java.</tt>".
+*/
+protected final Class<?> defineClass(String name, byte[] b, int off, int len,
+ProtectionDomain protectionDomain)
+throws ClassFormatError
+{
+protectionDomain = preDefineClass(name, protectionDomain);
+String source = defineClassSourceLocation(protectionDomain);
+Class<?> c = defineClass1(name, b, off, len, protectionDomain, source);
+postDefineClass(c, protectionDomain);
+return c;
+}
+/**
+* Converts a {@link java.nio.ByteBuffer <tt>ByteBuffer</tt>}
+* into an instance of class <tt>Class</tt>,
+* with an optional <tt>ProtectionDomain</tt>.  If the domain is
+* <tt>null</tt>, then a default domain will be assigned to the class as
+* specified in the documentation for {@link #defineClass(String, byte[],
+* int, int)}.  Before the class can be used it must be resolved.
+*
+* <p>The rules about the first class defined in a package determining the
+* set of certificates for the package, and the restrictions on class names
+* are identical to those specified in the documentation for {@link
+* #defineClass(String, byte[], int, int, ProtectionDomain)}.
+*
+* <p> An invocation of this method of the form
+* <i>cl</i><tt>.defineClass(</tt><i>name</i><tt>,</tt>
+* <i>bBuffer</i><tt>,</tt> <i>pd</i><tt>)</tt> yields exactly the same
+* result as the statements
+*
+*<p> <tt>
+* ...<br>
+* byte[] temp = new byte[bBuffer.{@link
+* java.nio.ByteBuffer#remaining remaining}()];<br>
+*     bBuffer.{@link java.nio.ByteBuffer#get(byte[])
+* get}(temp);<br>
+*     return {@link #defineClass(String, byte[], int, int, ProtectionDomain)
+* cl.defineClass}(name, temp, 0,
+* temp.length, pd);<br>
+* </tt></p>
+*
+* @param  name
+*         The expected <a href="#name">binary name</a>. of the class, or
+*         <tt>null</tt> if not known
+*
+* @param  b
+*         The bytes that make up the class data. The bytes from positions
+*         <tt>b.position()</tt> through <tt>b.position() + b.limit() -1
+*         </tt> should have the format of a valid class file as defined by
+*         <cite>The Java&trade; Virtual Machine Specification</cite>.
+*
+* @param  protectionDomain
+*         The ProtectionDomain of the class, or <tt>null</tt>.
+*
+* @return  The <tt>Class</tt> object created from the data,
+*          and optional <tt>ProtectionDomain</tt>.
+*
+* @throws  ClassFormatError
+*          If the data did not contain a valid class.
+*
+* @throws  NoClassDefFoundError
+*          If <tt>name</tt> is not equal to the <a href="#name">binary
+*          name</a> of the class specified by <tt>b</tt>
+*
+* @throws  SecurityException
+*          If an attempt is made to add this class to a package that
+*          contains classes that were signed by a different set of
+*          certificates than this class, or if <tt>name</tt> begins with
+*          "<tt>java.</tt>".
+*
+* @see      #defineClass(String, byte[], int, int, ProtectionDomain)
+*
+* @since  1.5
+*/
+protected final Class<?> defineClass(String name, java.nio.ByteBuffer b,
+ProtectionDomain protectionDomain)
+throws ClassFormatError
+{
+int len = b.remaining();
+// Use byte[] if not a direct ByteBufer:
+if (!b.isDirect()) {
+if (b.hasArray()) {
+return defineClass(name, b.array(),
+b.position() + b.arrayOffset(), len,
+protectionDomain);
+} else {
+// no array, or read-only array
+byte[] tb = new byte[len];
+b.get(tb);  // get bytes out of byte buffer.
+return defineClass(name, tb, 0, len, protectionDomain);
+}
+}
+protectionDomain = preDefineClass(name, protectionDomain);
+String source = defineClassSourceLocation(protectionDomain);
+Class<?> c = defineClass2(name, b, b.position(), len, protectionDomain, source);
+postDefineClass(c, protectionDomain);
+return c;
+}
+private native Class<?> defineClass1(String name, byte[] b, int off, int len,
+ProtectionDomain pd, String source);
+private native Class<?> defineClass2(String name, java.nio.ByteBuffer b,
+int off, int len, ProtectionDomain pd,
+String source);
+// true if the name is null or has the potential to be a valid binary name
+private boolean checkName(String name) {
+if ((name == null) || (name.length() == 0))
+return true;
+if ((name.indexOf('/') != -1) || (name.charAt(0) == '['))
+return false;
+return true;
+}
+private void checkCerts(String name, CodeSource cs) {
+int i = name.lastIndexOf('.');
+String pname = (i == -1) ? "" : name.substring(0, i);
+Certificate[] certs = null;
+if (cs != null) {
+certs = cs.getCertificates();
+}
+Certificate[] pcerts = null;
+if (parallelLockMap == null) {
+synchronized (this) {
+pcerts = package2certs.get(pname);
+if (pcerts == null) {
+package2certs.put(pname, (certs == null? nocerts:certs));
+}
+}
+} else {
+pcerts = ((ConcurrentHashMap<String, Certificate[]>)package2certs).
+putIfAbsent(pname, (certs == null? nocerts:certs));
+}
+if (pcerts != null && !compareCerts(pcerts, certs)) {
+throw new SecurityException("class \""+ name +
+"\"'s signer information does not match signer information of other classes in the same package");
+}
+}
+/**
+* check to make sure the certs for the new class (certs) are the same as
+* the certs for the first class inserted in the package (pcerts)
+*/
+private boolean compareCerts(Certificate[] pcerts,
+Certificate[] certs)
+{
+// certs can be null, indicating no certs.
+if ((certs == null) || (certs.length == 0)) {
+return pcerts.length == 0;
+}
+// the length must be the same at this point
+if (certs.length != pcerts.length)
+return false;
+// go through and make sure all the certs in one array
+// are in the other and vice-versa.
+boolean match;
+for (Certificate cert : certs) {
+match = false;
+for (Certificate pcert : pcerts) {
+if (cert.equals(pcert)) {
+match = true;
+break;
+}
+}
+if (!match) return false;
+}
+// now do the same for pcerts
+for (Certificate pcert : pcerts) {
+match = false;
+for (Certificate cert : certs) {
+if (pcert.equals(cert)) {
+match = true;
+break;
+}
+}
+if (!match) return false;
+}
+return true;
+}
+/**
+* Links the specified class.  This (misleadingly named) method may be
+* used by a class loader to link a class.  If the class <tt>c</tt> has
+* already been linked, then this method simply returns. Otherwise, the
+* class is linked as described in the "Execution" chapter of
+* <cite>The Java&trade; Language Specification</cite>.
+*
+* @param  c
+*         The class to link
+*
+* @throws  NullPointerException
+*          If <tt>c</tt> is <tt>null</tt>.
+*
+* @see  #defineClass(String, byte[], int, int)
+*/
+protected final void resolveClass(Class<?> c) {
+resolveClass0(c);
+}
+private native void resolveClass0(Class<?> c);
+/**
+* Finds a class with the specified <a href="#name">binary name</a>,
+* loading it if necessary.
+*
+* <p> This method loads the class through the system class loader (see
+* {@link #getSystemClassLoader()}).  The <tt>Class</tt> object returned
+* might have more than one <tt>ClassLoader</tt> associated with it.
+* Subclasses of <tt>ClassLoader</tt> need not usually invoke this method,
+* because most class loaders need to override just {@link
+* #findClass(String)}.  </p>
+*
+* @param  name
+*         The <a href="#name">binary name</a> of the class
+*
+* @return  The <tt>Class</tt> object for the specified <tt>name</tt>
+*
+* @throws  ClassNotFoundException
+*          If the class could not be found
+*
+* @see  #ClassLoader(ClassLoader)
+* @see  #getParent()
+*/
+protected final Class<?> findSystemClass(String name)
+throws ClassNotFoundException
+{
+ClassLoader system = getSystemClassLoader();
+if (system == null) {
+if (!checkName(name))
+throw new ClassNotFoundException(name);
+Class<?> cls = findBootstrapClass(name);
+if (cls == null) {
+throw new ClassNotFoundException(name);
+}
+return cls;
+}
+return system.loadClass(name);
+}
+/**
+* Returns a class loaded by the bootstrap class loader;
+* or return null if not found.
+*/
+private Class<?> findBootstrapClassOrNull(String name)
+{
+if (!checkName(name)) return null;
+return findBootstrapClass(name);
+}
+// return null if not found
+private native Class<?> findBootstrapClass(String name);
+/**
+* Returns the class with the given <a href="#name">binary name</a> if this
+* loader has been recorded by the Java virtual machine as an initiating
+* loader of a class with that <a href="#name">binary name</a>.  Otherwise
+* <tt>null</tt> is returned.
+*
+* @param  name
+*         The <a href="#name">binary name</a> of the class
+*
+* @return  The <tt>Class</tt> object, or <tt>null</tt> if the class has
+*          not been loaded
+*
+* @since  1.1
+*/
+protected final Class<?> findLoadedClass(String name) {
+if (!checkName(name))
+return null;
+return findLoadedClass0(name);
+}
+private native final Class<?> findLoadedClass0(String name);
+/**
+* Sets the signers of a class.  This should be invoked after defining a
+* class.
+*
+* @param  c
+*         The <tt>Class</tt> object
+*
+* @param  signers
+*         The signers for the class
+*
+* @since  1.1
+*/
+protected final void setSigners(Class<?> c, Object[] signers) {
+c.setSigners(signers);
+}
+// -- Resource --
+/**
+* Finds the resource with the given name.  A resource is some data
+* (images, audio, text, etc) that can be accessed by class code in a way
+* that is independent of the location of the code.
+*
+* <p> The name of a resource is a '<tt>/</tt>'-separated path name that
+* identifies the resource.
+*
+* <p> This method will first search the parent class loader for the
+* resource; if the parent is <tt>null</tt> the path of the class loader
+* built-in to the virtual machine is searched.  That failing, this method
+* will invoke {@link #findResource(String)} to find the resource.  </p>
+*
+* @apiNote When overriding this method it is recommended that an
+* implementation ensures that any delegation is consistent with the {@link
+* #getResources(java.lang.String) getResources(String)} method.
+*
+* @param  name
+*         The resource name
+*
+* @return  A <tt>URL</tt> object for reading the resource, or
+*          <tt>null</tt> if the resource could not be found or the invoker
+*          doesn't have adequate  privileges to get the resource.
+*
+* @since  1.1
+*/
+public URL getResource(String name) {
+URL url;
+if (parent != null) {
+url = parent.getResource(name);
+} else {
+url = getBootstrapResource(name);
+}
+if (url == null) {
+url = findResource(name);
+}
+return url;
+}
+/**
+* Finds all the resources with the given name. A resource is some data
+* (images, audio, text, etc) that can be accessed by class code in a way
+* that is independent of the location of the code.
+*
+* <p>The name of a resource is a <tt>/</tt>-separated path name that
+* identifies the resource.
+*
+* <p> The search order is described in the documentation for {@link
+* #getResource(String)}.  </p>
+*
+* @apiNote When overriding this method it is recommended that an
+* implementation ensures that any delegation is consistent with the {@link
+* #getResource(java.lang.String) getResource(String)} method. This should
+* ensure that the first element returned by the Enumeration's
+* {@code nextElement} method is the same resource that the
+* {@code getResource(String)} method would return.
+*
+* @param  name
+*         The resource name
+*
+* @return  An enumeration of {@link java.net.URL <tt>URL</tt>} objects for
+*          the resource.  If no resources could  be found, the enumeration
+*          will be empty.  Resources that the class loader doesn't have
+*          access to will not be in the enumeration.
+*
+* @throws  IOException
+*          If I/O errors occur
+*
+* @see  #findResources(String)
+*
+* @since  1.2
+*/
+public Enumeration<URL> getResources(String name) throws IOException {
+@SuppressWarnings("unchecked")
+Enumeration<URL>[] tmp = (Enumeration<URL>[]) new Enumeration<?>[2];
+if (parent != null) {
+tmp[0] = parent.getResources(name);
+} else {
+tmp[0] = getBootstrapResources(name);
+}
+tmp[1] = findResources(name);
+return new CompoundEnumeration<>(tmp);
+}
+/**
+* Finds the resource with the given name. Class loader implementations
+* should override this method to specify where to find resources.
+*
+* @param  name
+*         The resource name
+*
+* @return  A <tt>URL</tt> object for reading the resource, or
+*          <tt>null</tt> if the resource could not be found
+*
+* @since  1.2
+*/
+protected URL findResource(String name) {
+return null;
+}
+/**
+* Returns an enumeration of {@link java.net.URL <tt>URL</tt>} objects
+* representing all the resources with the given name. Class loader
+* implementations should override this method to specify where to load
+* resources from.
+*
+* @param  name
+*         The resource name
+*
+* @return  An enumeration of {@link java.net.URL <tt>URL</tt>} objects for
+*          the resources
+*
+* @throws  IOException
+*          If I/O errors occur
+*
+* @since  1.2
+*/
+protected Enumeration<URL> findResources(String name) throws IOException {
+return java.util.Collections.emptyEnumeration();
+}
+/**
+* Registers the caller as parallel capable.
+* The registration succeeds if and only if all of the following
+* conditions are met:
+* <ol>
+* <li> no instance of the caller has been created</li>
+* <li> all of the super classes (except class Object) of the caller are
+* registered as parallel capable</li>
+* </ol>
+* <p>Note that once a class loader is registered as parallel capable, there
+* is no way to change it back.</p>
+*
+* @return  true if the caller is successfully registered as
+*          parallel capable and false if otherwise.
+*
+* @since   1.7
+*/
+@CallerSensitive
+protected static boolean registerAsParallelCapable() {
+Class<? extends ClassLoader> callerClass =
+Reflection.getCallerClass().asSubclass(ClassLoader.class);
+return ParallelLoaders.register(callerClass);
+}
+/**
+* Find a resource of the specified name from the search path used to load
+* classes.  This method locates the resource through the system class
+* loader (see {@link #getSystemClassLoader()}).
+*
+* @param  name
+*         The resource name
+*
+* @return  A {@link java.net.URL <tt>URL</tt>} object for reading the
+*          resource, or <tt>null</tt> if the resource could not be found
+*
+* @since  1.1
+*/
+public static URL getSystemResource(String name) {
+ClassLoader system = getSystemClassLoader();
+if (system == null) {
+return getBootstrapResource(name);
+}
+return system.getResource(name);
+}
+/**
+* Finds all resources of the specified name from the search path used to
+* load classes.  The resources thus found are returned as an
+* {@link java.util.Enumeration <tt>Enumeration</tt>} of {@link
+* java.net.URL <tt>URL</tt>} objects.
+*
+* <p> The search order is described in the documentation for {@link
+* #getSystemResource(String)}.  </p>
+*
+* @param  name
+*         The resource name
+*
+* @return  An enumeration of resource {@link java.net.URL <tt>URL</tt>}
+*          objects
+*
+* @throws  IOException
+*          If I/O errors occur
+* @since  1.2
+*/
+public static Enumeration<URL> getSystemResources(String name)
+throws IOException
+{
+ClassLoader system = getSystemClassLoader();
+if (system == null) {
+return getBootstrapResources(name);
+}
+return system.getResources(name);
+}
+/**
+* Find resources from the VM's built-in classloader.
+*/
+private static URL getBootstrapResource(String name) {
+URLClassPath ucp = getBootstrapClassPath();
+Resource res = ucp.getResource(name);
+return res != null ? res.getURL() : null;
+}
+/**
+* Find resources from the VM's built-in classloader.
+*/
+private static Enumeration<URL> getBootstrapResources(String name)
+throws IOException
+{
+final Enumeration<Resource> e =
+getBootstrapClassPath().getResources(name);
+return new Enumeration<URL> () {
+public URL nextElement() {
+return e.nextElement().getURL();
+}
+public boolean hasMoreElements() {
+return e.hasMoreElements();
+}
+};
+}
+// Returns the URLClassPath that is used for finding system resources.
+static URLClassPath getBootstrapClassPath() {
+return sun.misc.Launcher.getBootstrapClassPath();
+}
+/**
+* Returns an input stream for reading the specified resource.
+*
+* <p> The search order is described in the documentation for {@link
+* #getResource(String)}.  </p>
+*
+* @param  name
+*         The resource name
+*
+* @return  An input stream for reading the resource, or <tt>null</tt>
+*          if the resource could not be found
+*
+* @since  1.1
+*/
+public InputStream getResourceAsStream(String name) {
+URL url = getResource(name);
+try {
+return url != null ? url.openStream() : null;
+} catch (IOException e) {
+return null;
+}
+}
+/**
+* Open for reading, a resource of the specified name from the search path
+* used to load classes.  This method locates the resource through the
+* system class loader (see {@link #getSystemClassLoader()}).
+*
+* @param  name
+*         The resource name
+*
+* @return  An input stream for reading the resource, or <tt>null</tt>
+*          if the resource could not be found
+*
+* @since  1.1
+*/
+public static InputStream getSystemResourceAsStream(String name) {
+URL url = getSystemResource(name);
+try {
+return url != null ? url.openStream() : null;
+} catch (IOException e) {
+return null;
+}
+}
+// -- Hierarchy --
+/**
+* Returns the parent class loader for delegation. Some implementations may
+* use <tt>null</tt> to represent the bootstrap class loader. This method
+* will return <tt>null</tt> in such implementations if this class loader's
+* parent is the bootstrap class loader.
+*
+* <p> If a security manager is present, and the invoker's class loader is
+* not <tt>null</tt> and is not an ancestor of this class loader, then this
+* method invokes the security manager's {@link
+* SecurityManager#checkPermission(java.security.Permission)
+* <tt>checkPermission</tt>} method with a {@link
+* RuntimePermission#RuntimePermission(String)
+* <tt>RuntimePermission("getClassLoader")</tt>} permission to verify
+* access to the parent class loader is permitted.  If not, a
+* <tt>SecurityException</tt> will be thrown.  </p>
+*
+* @return  The parent <tt>ClassLoader</tt>
+*
+* @throws  SecurityException
+*          If a security manager exists and its <tt>checkPermission</tt>
+*          method doesn't allow access to this class loader's parent class
+*          loader.
+*
+* @since  1.2
+*/
+@CallerSensitive
+public final ClassLoader getParent() {
+if (parent == null)
+return null;
+SecurityManager sm = System.getSecurityManager();
+if (sm != null) {
+checkClassLoaderPermission(this, Reflection.getCallerClass());
+}
+return parent;
+}
+/**
+* Returns the system class loader for delegation.  This is the default
+* delegation parent for new <tt>ClassLoader</tt> instances, and is
+* typically the class loader used to start the application.
+*
+* <p> This method is first invoked early in the runtime's startup
+* sequence, at which point it creates the system class loader and sets it
+* as the context class loader of the invoking <tt>Thread</tt>.
+*
+* <p> The default system class loader is an implementation-dependent
+* instance of this class.
+*
+* <p> If the system property "<tt>java.system.class.loader</tt>" is defined
+* when this method is first invoked then the value of that property is
+* taken to be the name of a class that will be returned as the system
+* class loader.  The class is loaded using the default system class loader
+* and must define a public constructor that takes a single parameter of
+* type <tt>ClassLoader</tt> which is used as the delegation parent.  An
+* instance is then created using this constructor with the default system
+* class loader as the parameter.  The resulting class loader is defined
+* to be the system class loader.
+*
+* <p> If a security manager is present, and the invoker's class loader is
+* not <tt>null</tt> and the invoker's class loader is not the same as or
+* an ancestor of the system class loader, then this method invokes the
+* security manager's {@link
+* SecurityManager#checkPermission(java.security.Permission)
+* <tt>checkPermission</tt>} method with a {@link
+* RuntimePermission#RuntimePermission(String)
+* <tt>RuntimePermission("getClassLoader")</tt>} permission to verify
+* access to the system class loader.  If not, a
+* <tt>SecurityException</tt> will be thrown.  </p>
+*
+* @return  The system <tt>ClassLoader</tt> for delegation, or
+*          <tt>null</tt> if none
+*
+* @throws  SecurityException
+*          If a security manager exists and its <tt>checkPermission</tt>
+*          method doesn't allow access to the system class loader.
+*
+* @throws  IllegalStateException
+*          If invoked recursively during the construction of the class
+*          loader specified by the "<tt>java.system.class.loader</tt>"
+*          property.
+*
+* @throws  Error
+*          If the system property "<tt>java.system.class.loader</tt>"
+*          is defined but the named class could not be loaded, the
+*          provider class does not define the required constructor, or an
+*          exception is thrown by that constructor when it is invoked. The
+*          underlying cause of the error can be retrieved via the
+*          {@link Throwable#getCause()} method.
+*
+* @revised  1.4
+*/
+@CallerSensitive
+public static ClassLoader getSystemClassLoader() {
+initSystemClassLoader();
+if (scl == null) {
+return null;
+}
+SecurityManager sm = System.getSecurityManager();
+if (sm != null) {
+checkClassLoaderPermission(scl, Reflection.getCallerClass());
+}
+return scl;
+}
+private static synchronized void initSystemClassLoader() {
+if (!sclSet) {
+if (scl != null)
+throw new IllegalStateException("recursive invocation");
+sun.misc.Launcher l = sun.misc.Launcher.getLauncher();
+if (l != null) {
+Throwable oops = null;
+scl = l.getClassLoader();
+try {
+scl = AccessController.doPrivileged(
+new SystemClassLoaderAction(scl));
+} catch (PrivilegedActionException pae) {
+oops = pae.getCause();
+if (oops instanceof InvocationTargetException) {
+oops = oops.getCause();
+}
+}
+if (oops != null) {
+if (oops instanceof Error) {
+throw (Error) oops;
+} else {
+// wrap the exception
+throw new Error(oops);
+}
+}
+}
+sclSet = true;
+}
+}
+// Returns true if the specified class loader can be found in this class
+// loader's delegation chain.
+boolean isAncestor(ClassLoader cl) {
+ClassLoader acl = this;
+do {
+acl = acl.parent;
+if (cl == acl) {
+return true;
+}
+} while (acl != null);
+return false;
+}
+// Tests if class loader access requires "getClassLoader" permission
+// check.  A class loader 'from' can access class loader 'to' if
+// class loader 'from' is same as class loader 'to' or an ancestor
+// of 'to'.  The class loader in a system domain can access
+// any class loader.
+private static boolean needsClassLoaderPermissionCheck(ClassLoader from,
+ClassLoader to)
+{
+if (from == to)
+return false;
+if (from == null)
+return false;
+return !to.isAncestor(from);
+}
+// Returns the class's class loader, or null if none.
+static ClassLoader getClassLoader(Class<?> caller) {
+// This can be null if the VM is requesting it
+if (caller == null) {
+return null;
+}
+// Circumvent security check since this is package-private
+return caller.getClassLoader0();
+}
+static void checkClassLoaderPermission(ClassLoader cl, Class<?> caller) {
+SecurityManager sm = System.getSecurityManager();
+if (sm != null) {
+// caller can be null if the VM is requesting it
+ClassLoader ccl = getClassLoader(caller);
+if (needsClassLoaderPermissionCheck(ccl, cl)) {
+sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);
+}
+}
+}
+// The class loader for the system
+// @GuardedBy("ClassLoader.class")
+private static ClassLoader scl;
+// Set to true once the system class loader has been set
+// @GuardedBy("ClassLoader.class")
+private static boolean sclSet;
+// -- Package --
+/**
+* Defines a package by name in this <tt>ClassLoader</tt>.  This allows
+* class loaders to define the packages for their classes. Packages must
+* be created before the class is defined, and package names must be
+* unique within a class loader and cannot be redefined or changed once
+* created.
+*
+* @param  name
+*         The package name
+*
+* @param  specTitle
+*         The specification title
+*
+* @param  specVersion
+*         The specification version
+*
+* @param  specVendor
+*         The specification vendor
+*
+* @param  implTitle
+*         The implementation title
+*
+* @param  implVersion
+*         The implementation version
+*
+* @param  implVendor
+*         The implementation vendor
+*
+* @param  sealBase
+*         If not <tt>null</tt>, then this package is sealed with
+*         respect to the given code source {@link java.net.URL
+*         <tt>URL</tt>}  object.  Otherwise, the package is not sealed.
+*
+* @return  The newly defined <tt>Package</tt> object
+*
+* @throws  IllegalArgumentException
+*          If package name duplicates an existing package either in this
+*          class loader or one of its ancestors
+*
+* @since  1.2
+*/
+protected Package definePackage(String name, String specTitle,
+String specVersion, String specVendor,
+String implTitle, String implVersion,
+String implVendor, URL sealBase)
+throws IllegalArgumentException
+{
+synchronized (packages) {
+Package pkg = getPackage(name);
+if (pkg != null) {
+throw new IllegalArgumentException(name);
+}
+pkg = new Package(name, specTitle, specVersion, specVendor,
+implTitle, implVersion, implVendor,
+sealBase, this);
+packages.put(name, pkg);
+return pkg;
+}
+}
+/**
+* Returns a <tt>Package</tt> that has been defined by this class loader
+* or any of its ancestors.
+*
+* @param  name
+*         The package name
+*
+* @return  The <tt>Package</tt> corresponding to the given name, or
+*          <tt>null</tt> if not found
+*
+* @since  1.2
+*/
+protected Package getPackage(String name) {
+Package pkg;
+synchronized (packages) {
+pkg = packages.get(name);
+}
+if (pkg == null) {
+if (parent != null) {
+pkg = parent.getPackage(name);
+} else {
+pkg = Package.getSystemPackage(name);
+}
+if (pkg != null) {
+synchronized (packages) {
+Package pkg2 = packages.get(name);
+if (pkg2 == null) {
+packages.put(name, pkg);
+} else {
+pkg = pkg2;
+}
+}
+}
+}
+return pkg;
+}
+/**
+* Returns all of the <tt>Packages</tt> defined by this class loader and
+* its ancestors.
+*
+* @return  The array of <tt>Package</tt> objects defined by this
+*          <tt>ClassLoader</tt>
+*
+* @since  1.2
+*/
+protected Package[] getPackages() {
+Map<String, Package> map;
+synchronized (packages) {
+map = new HashMap<>(packages);
+}
+Package[] pkgs;
+if (parent != null) {
+pkgs = parent.getPackages();
+} else {
+pkgs = Package.getSystemPackages();
+}
+if (pkgs != null) {
+for (Package pkg : pkgs) {
+String pkgName = pkg.getName();
+if (map.get(pkgName) == null) {
+map.put(pkgName, pkg);
+}
+}
+}
+return map.values().toArray(new Package[map.size()]);
+}
+// -- Native library access --
+/**
+* Returns the absolute path name of a native library.  The VM invokes this
+* method to locate the native libraries that belong to classes loaded with
+* this class loader. If this method returns <tt>null</tt>, the VM
+* searches the library along the path specified as the
+* "<tt>java.library.path</tt>" property.
+*
+* @param  libname
+*         The library name
+*
+* @return  The absolute path of the native library
+*
+* @see  System#loadLibrary(String)
+* @see  System#mapLibraryName(String)
+*
+* @since  1.2
+*/
+protected String findLibrary(String libname) {
+return null;
+}
+/**
+* The inner class NativeLibrary denotes a loaded native library instance.
+* Every classloader contains a vector of loaded native libraries in the
+* private field <tt>nativeLibraries</tt>.  The native libraries loaded
+* into the system are entered into the <tt>systemNativeLibraries</tt>
+* vector.
+*
+* <p> Every native library requires a particular version of JNI. This is
+* denoted by the private <tt>jniVersion</tt> field.  This field is set by
+* the VM when it loads the library, and used by the VM to pass the correct
+* version of JNI to the native methods.  </p>
+*
+* @see      ClassLoader
+* @since    1.2
+*/
+static class NativeLibrary {
+// opaque handle to native library, used in native code.
+long handle;
+// the version of JNI environment the native library requires.
+private int jniVersion;
+// the class from which the library is loaded, also indicates
+// the loader this native library belongs.
+private final Class<?> fromClass;
+// the canonicalized name of the native library.
+// or static library name
+String name;
+// Indicates if the native library is linked into the VM
+boolean isBuiltin;
+// Indicates if the native library is loaded
+boolean loaded;
+native void load(String name, boolean isBuiltin);
+native long find(String name);
+native void unload(String name, boolean isBuiltin);
+static native String findBuiltinLib(String name);
+public NativeLibrary(Class<?> fromClass, String name, boolean isBuiltin) {
+this.name = name;
+this.fromClass = fromClass;
+this.isBuiltin = isBuiltin;
+}
+protected void finalize() {
+synchronized (loadedLibraryNames) {
+if (fromClass.getClassLoader() != null && loaded) {
+/* remove the native library name */
+int size = loadedLibraryNames.size();
+for (int i = 0; i < size; i++) {
+if (name.equals(loadedLibraryNames.elementAt(i))) {
+loadedLibraryNames.removeElementAt(i);
+break;
+}
+}
+/* unload the library. */
+ClassLoader.nativeLibraryContext.push(this);
+try {
+unload(name, isBuiltin);
+} finally {
+ClassLoader.nativeLibraryContext.pop();
+}
+}
+}
+}
+// Invoked in the VM to determine the context class in
+// JNI_Load/JNI_Unload
+static Class<?> getFromClass() {
+return ClassLoader.nativeLibraryContext.peek().fromClass;
+}
+}
+// All native library names we've loaded.
+private static Vector<String> loadedLibraryNames = new Vector<>();
+// Native libraries belonging to system classes.
+private static Vector<NativeLibrary> systemNativeLibraries
+= new Vector<>();
+// Native libraries associated with the class loader.
+private Vector<NativeLibrary> nativeLibraries = new Vector<>();
+// native libraries being loaded/unloaded.
+private static Stack<NativeLibrary> nativeLibraryContext = new Stack<>();
+// The paths searched for libraries
+private static String usr_paths[];
+private static String sys_paths[];
+private static String[] initializePath(String propname) {
+String ldpath = System.getProperty(propname, "");
+String ps = File.pathSeparator;
+int ldlen = ldpath.length();
+int i, j, n;
+// Count the separators in the path
+i = ldpath.indexOf(ps);
+n = 0;
+while (i >= 0) {
+n++;
+i = ldpath.indexOf(ps, i + 1);
+}
+// allocate the array of paths - n :'s = n + 1 path elements
+String[] paths = new String[n + 1];
+// Fill the array with paths from the ldpath
+n = i = 0;
+j = ldpath.indexOf(ps);
+while (j >= 0) {
+if (j - i > 0) {
+paths[n++] = ldpath.substring(i, j);
+} else if (j - i == 0) {
+paths[n++] = ".";
+}
+i = j + 1;
+j = ldpath.indexOf(ps, i);
+}
+paths[n] = ldpath.substring(i, ldlen);
+return paths;
+}
+// Invoked in the java.lang.Runtime class to implement load and loadLibrary.
+static void loadLibrary(Class<?> fromClass, String name,
+boolean isAbsolute) {
+ClassLoader loader =
+(fromClass == null) ? null : fromClass.getClassLoader();
+if (sys_paths == null) {
+usr_paths = initializePath("java.library.path");
+sys_paths = initializePath("sun.boot.library.path");
+}
+if (isAbsolute) {
+if (loadLibrary0(fromClass, new File(name))) {
+return;
+}
+throw new UnsatisfiedLinkError("Can't load library: " + name);
+}
+if (loader != null) {
+String libfilename = loader.findLibrary(name);
+if (libfilename != null) {
+File libfile = new File(libfilename);
+if (!libfile.isAbsolute()) {
+throw new UnsatisfiedLinkError(
+"ClassLoader.findLibrary failed to return an absolute path: " + libfilename);
+}
+if (loadLibrary0(fromClass, libfile)) {
+return;
+}
+throw new UnsatisfiedLinkError("Can't load " + libfilename);
+}
+}
+for (String sys_path : sys_paths) {
+File libfile = new File(sys_path, System.mapLibraryName(name));
+if (loadLibrary0(fromClass, libfile)) {
+return;
+}
+libfile = ClassLoaderHelper.mapAlternativeName(libfile);
+if (libfile != null && loadLibrary0(fromClass, libfile)) {
+return;
+}
+}
+if (loader != null) {
+for (String usr_path : usr_paths) {
+File libfile = new File(usr_path, System.mapLibraryName(name));
+if (loadLibrary0(fromClass, libfile)) {
+return;
+}
+libfile = ClassLoaderHelper.mapAlternativeName(libfile);
+if (libfile != null && loadLibrary0(fromClass, libfile)) {
+return;
+}
+}
+}
+// Oops, it failed
+throw new UnsatisfiedLinkError("no " + name + " in java.library.path");
+}
+private static boolean loadLibrary0(Class<?> fromClass, final File file) {
+// Check to see if we're attempting to access a static library
+String name = NativeLibrary.findBuiltinLib(file.getName());
+boolean isBuiltin = (name != null);
+if (!isBuiltin) {
+name = AccessController.doPrivileged(
+new PrivilegedAction<String>() {
+public String run() {
+try {
+return file.exists() ? file.getCanonicalPath() : null;
+} catch (IOException e) {
+return null;
+}
+}
+});
+if (name == null) {
+return false;
+}
+}
+ClassLoader loader =
+(fromClass == null) ? null : fromClass.getClassLoader();
+Vector<NativeLibrary> libs =
+loader != null ? loader.nativeLibraries : systemNativeLibraries;
+synchronized (libs) {
+int size = libs.size();
+for (int i = 0; i < size; i++) {
+NativeLibrary lib = libs.elementAt(i);
+if (name.equals(lib.name)) {
+return true;
+}
+}
+synchronized (loadedLibraryNames) {
+if (loadedLibraryNames.contains(name)) {
+throw new UnsatisfiedLinkError
+("Native Library " +
+name +
+" already loaded in another classloader");
+}
+/* If the library is being loaded (must be by the same thread,
+* because Runtime.load and Runtime.loadLibrary are
+* synchronous). The reason is can occur is that the JNI_OnLoad
+* function can cause another loadLibrary invocation.
+*
+* Thus we can use a static stack to hold the list of libraries
+* we are loading.
+*
+* If there is a pending load operation for the library, we
+* immediately return success; otherwise, we raise
+* UnsatisfiedLinkError.
+*/
+int n = nativeLibraryContext.size();
+for (int i = 0; i < n; i++) {
+NativeLibrary lib = nativeLibraryContext.elementAt(i);
+if (name.equals(lib.name)) {
+if (loader == lib.fromClass.getClassLoader()) {
+return true;
+} else {
+throw new UnsatisfiedLinkError
+("Native Library " +
+name +
+" is being loaded in another classloader");
+}
+}
+}
+NativeLibrary lib = new NativeLibrary(fromClass, name, isBuiltin);
+nativeLibraryContext.push(lib);
+try {
+lib.load(name, isBuiltin);
+} finally {
+nativeLibraryContext.pop();
+}
+if (lib.loaded) {
+loadedLibraryNames.addElement(name);
+libs.addElement(lib);
+return true;
+}
+return false;
+}
+}
+}
+// Invoked in the VM class linking code.
+static long findNative(ClassLoader loader, String name) {
+Vector<NativeLibrary> libs =
+loader != null ? loader.nativeLibraries : systemNativeLibraries;
+synchronized (libs) {
+int size = libs.size();
+for (int i = 0; i < size; i++) {
+NativeLibrary lib = libs.elementAt(i);
+long entry = lib.find(name);
+if (entry != 0)
+return entry;
+}
+}
+return 0;
+}
+// -- Assertion management --
+final Object assertionLock;
+// The default toggle for assertion checking.
+// @GuardedBy("assertionLock")
+private boolean defaultAssertionStatus = false;
+// Maps String packageName to Boolean package default assertion status Note
+// that the default package is placed under a null map key.  If this field
+// is null then we are delegating assertion status queries to the VM, i.e.,
+// none of this ClassLoader's assertion status modification methods have
+// been invoked.
+// @GuardedBy("assertionLock")
+private Map<String, Boolean> packageAssertionStatus = null;
+// Maps String fullyQualifiedClassName to Boolean assertionStatus If this
+// field is null then we are delegating assertion status queries to the VM,
+// i.e., none of this ClassLoader's assertion status modification methods
+// have been invoked.
+// @GuardedBy("assertionLock")
+Map<String, Boolean> classAssertionStatus = null;
+/**
+* Sets the default assertion status for this class loader.  This setting
+* determines whether classes loaded by this class loader and initialized
+* in the future will have assertions enabled or disabled by default.
+* This setting may be overridden on a per-package or per-class basis by
+* invoking {@link #setPackageAssertionStatus(String, boolean)} or {@link
+* #setClassAssertionStatus(String, boolean)}.
+*
+* @param  enabled
+*         <tt>true</tt> if classes loaded by this class loader will
+*         henceforth have assertions enabled by default, <tt>false</tt>
+*         if they will have assertions disabled by default.
+*
+* @since  1.4
+*/
+public void setDefaultAssertionStatus(boolean enabled) {
+synchronized (assertionLock) {
+if (classAssertionStatus == null)
+initializeJavaAssertionMaps();
+defaultAssertionStatus = enabled;
+}
+}
+/**
+* Sets the package default assertion status for the named package.  The
+* package default assertion status determines the assertion status for
+* classes initialized in the future that belong to the named package or
+* any of its "subpackages".
+*
+* <p> A subpackage of a package named p is any package whose name begins
+* with "<tt>p.</tt>".  For example, <tt>javax.swing.text</tt> is a
+* subpackage of <tt>javax.swing</tt>, and both <tt>java.util</tt> and
+* <tt>java.lang.reflect</tt> are subpackages of <tt>java</tt>.
+*
+* <p> In the event that multiple package defaults apply to a given class,
+* the package default pertaining to the most specific package takes
+* precedence over the others.  For example, if <tt>javax.lang</tt> and
+* <tt>javax.lang.reflect</tt> both have package defaults associated with
+* them, the latter package default applies to classes in
+* <tt>javax.lang.reflect</tt>.
+*
+* <p> Package defaults take precedence over the class loader's default
+* assertion status, and may be overridden on a per-class basis by invoking
+* {@link #setClassAssertionStatus(String, boolean)}.  </p>
+*
+* @param  packageName
+*         The name of the package whose package default assertion status
+*         is to be set. A <tt>null</tt> value indicates the unnamed
+*         package that is "current"
+*         (see section 7.4.2 of
+*         <cite>The Java&trade; Language Specification</cite>.)
+*
+* @param  enabled
+*         <tt>true</tt> if classes loaded by this classloader and
+*         belonging to the named package or any of its subpackages will
+*         have assertions enabled by default, <tt>false</tt> if they will
+*         have assertions disabled by default.
+*
+* @since  1.4
+*/
+public void setPackageAssertionStatus(String packageName,
+boolean enabled) {
+synchronized (assertionLock) {
+if (packageAssertionStatus == null)
+initializeJavaAssertionMaps();
+packageAssertionStatus.put(packageName, enabled);
+}
+}
+/**
+* Sets the desired assertion status for the named top-level class in this
+* class loader and any nested classes contained therein.  This setting
+* takes precedence over the class loader's default assertion status, and
+* over any applicable per-package default.  This method has no effect if
+* the named class has already been initialized.  (Once a class is
+* initialized, its assertion status cannot change.)
+*
+* <p> If the named class is not a top-level class, this invocation will
+* have no effect on the actual assertion status of any class. </p>
+*
+* @param  className
+*         The fully qualified class name of the top-level class whose
+*         assertion status is to be set.
+*
+* @param  enabled
+*         <tt>true</tt> if the named class is to have assertions
+*         enabled when (and if) it is initialized, <tt>false</tt> if the
+*         class is to have assertions disabled.
+*
+* @since  1.4
+*/
+public void setClassAssertionStatus(String className, boolean enabled) {
+synchronized (assertionLock) {
+if (classAssertionStatus == null)
+initializeJavaAssertionMaps();
+classAssertionStatus.put(className, enabled);
+}
+}
+/**
+* Sets the default assertion status for this class loader to
+* <tt>false</tt> and discards any package defaults or class assertion
+* status settings associated with the class loader.  This method is
+* provided so that class loaders can be made to ignore any command line or
+* persistent assertion status settings and "start with a clean slate."
+*
+* @since  1.4
+*/
+public void clearAssertionStatus() {
+/*
+* Whether or not "Java assertion maps" are initialized, set
+* them to empty maps, effectively ignoring any present settings.
+*/
+synchronized (assertionLock) {
+classAssertionStatus = new HashMap<>();
+packageAssertionStatus = new HashMap<>();
+defaultAssertionStatus = false;
+}
+}
+/**
+* Returns the assertion status that would be assigned to the specified
+* class if it were to be initialized at the time this method is invoked.
+* If the named class has had its assertion status set, the most recent
+* setting will be returned; otherwise, if any package default assertion
+* status pertains to this class, the most recent setting for the most
+* specific pertinent package default assertion status is returned;
+* otherwise, this class loader's default assertion status is returned.
+* </p>
+*
+* @param  className
+*         The fully qualified class name of the class whose desired
+*         assertion status is being queried.
+*
+* @return  The desired assertion status of the specified class.
+*
+* @see  #setClassAssertionStatus(String, boolean)
+* @see  #setPackageAssertionStatus(String, boolean)
+* @see  #setDefaultAssertionStatus(boolean)
+*
+* @since  1.4
+*/
+boolean desiredAssertionStatus(String className) {
+synchronized (assertionLock) {
+// assert classAssertionStatus   != null;
+// assert packageAssertionStatus != null;
+// Check for a class entry
+Boolean result = classAssertionStatus.get(className);
+if (result != null)
+return result.booleanValue();
+// Check for most specific package entry
+int dotIndex = className.lastIndexOf('.');
+if (dotIndex < 0) { // default package
+result = packageAssertionStatus.get(null);
+if (result != null)
+return result.booleanValue();
+}
+while(dotIndex > 0) {
+className = className.substring(0, dotIndex);
+result = packageAssertionStatus.get(className);
+if (result != null)
+return result.booleanValue();
+dotIndex = className.lastIndexOf('.', dotIndex-1);
+}
+// Return the classloader default
+return defaultAssertionStatus;
+}
+}
+// Set up the assertions with information provided by the VM.
+// Note: Should only be called inside a synchronized block
+private void initializeJavaAssertionMaps() {
+// assert Thread.holdsLock(assertionLock);
+classAssertionStatus = new HashMap<>();
+packageAssertionStatus = new HashMap<>();
+AssertionStatusDirectives directives = retrieveDirectives();
+for(int i = 0; i < directives.classes.length; i++)
+classAssertionStatus.put(directives.classes[i],
+directives.classEnabled[i]);
+for(int i = 0; i < directives.packages.length; i++)
+packageAssertionStatus.put(directives.packages[i],
+directives.packageEnabled[i]);
+defaultAssertionStatus = directives.deflt;
+}
+// Retrieves the assertion directives from the VM.
+private static native AssertionStatusDirectives retrieveDirectives();
+}
+class SystemClassLoaderAction
+implements PrivilegedExceptionAction<ClassLoader> {
+private ClassLoader parent;
+SystemClassLoaderAction(ClassLoader parent) {
+this.parent = parent;
+}
+public ClassLoader run() throws Exception {
+String cls = System.getProperty("java.system.class.loader");
+if (cls == null) {
+return parent;
+}
+Constructor<?> ctor = Class.forName(cls, true, parent)
+.getDeclaredConstructor(new Class<?>[] { ClassLoader.class });
+ClassLoader sys = (ClassLoader) ctor.newInstance(
+new Object[] { parent });
+Thread.currentThread().setContextClassLoader(sys);
+return sys;
+}
+}

changeset 25859	3317bb8137f4
parent 25167	6a8e55aba124
child 25991	e48157b42439