diff -r 2836ee97ee27 -r 8145ab9f5f86 jdk/src/share/classes/sun/invoke/util/VerifyAccess.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/sun/invoke/util/VerifyAccess.java	Wed Mar 23 23:02:31 2011 -0700
@@ -0,0 +1,210 @@
+/*
+ * Copyright (c) 2008, 2011, 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 sun.invoke.util;
+
+import java.lang.reflect.Modifier;
+import static java.lang.reflect.Modifier.*;
+
+/**
+ * This class centralizes information about the JVM's linkage access control.
+ * @author jrose
+ */
+public class VerifyAccess {
+
+    private VerifyAccess() { }  // cannot instantiate
+
+    private static final int PACKAGE_ONLY = 0;
+    private static final int ALL_ACCESS_MODES = (PUBLIC|PRIVATE|PROTECTED|PACKAGE_ONLY);
+    private static final boolean ALLOW_NESTMATE_ACCESS = false;
+
+    /**
+     * Evaluate the JVM linkage rules for access to the given method
+     * on behalf of a caller class which proposes to perform the access.
+     * Return true if the caller class has privileges to invoke a method
+     * or access a field with the given properties.
+     * This requires an accessibility check of the referencing class,
+     * plus an accessibility check of the member within the class,
+     * which depends on the member's modifier flags.
+     * <p>
+     * The relevant properties include the defining class ({@code defc})
+     * of the member, and its modifier flags ({@code mods}).
+     * Also relevant is the class used to make the initial symbolic reference
+     * to the member ({@code refc}).  If this latter class is not distinguished,
+     * the defining class should be passed for both arguments ({@code defc == refc}).
+     * <h3>JVM Specification, 5.4.4 "Access Control"</h3>
+     * A field or method R is accessible to a class or interface D if
+     * and only if any of the following conditions is true:<ul>
+     * <li>R is public.
+     * <li>R is protected and is declared in a class C, and D is either
+     *     a subclass of C or C itself.  Furthermore, if R is not
+     *     static, then the symbolic reference to R must contain a
+     *     symbolic reference to a class T, such that T is either a
+     *     subclass of D, a superclass of D or D itself.
+     * <li>R is either protected or has default access (that is,
+     *     neither public nor protected nor private), and is declared
+     *     by a class in the same runtime package as D.
+     * <li>R is private and is declared in D.
+     * </ul>
+     * This discussion of access control omits a related restriction
+     * on the target of a protected field access or method invocation
+     * (the target must be of class D or a subtype of D). That
+     * requirement is checked as part of the verification process
+     * (5.4.1); it is not part of link-time access control.
+     * @param refc the class used in the symbolic reference to the proposed member
+     * @param defc the class in which the proposed member is actually defined
+     * @param mods modifier flags for the proposed member
+     * @param lookupClass the class for which the access check is being made
+     * @return true iff the the accessing class can access such a member
+     */
+    public static boolean isMemberAccessible(Class<?> refc,  // symbolic ref class
+                                             Class<?> defc,  // actual def class
+                                             int      mods,  // actual member mods
+                                             Class<?> lookupClass) {
+        // Usually refc and defc are the same, but if they differ, verify them both.
+        if (refc != defc) {
+            if (!isClassAccessible(refc, lookupClass)) {
+                // Note that defc is verified in the switch below.
+                return false;
+            }
+            if ((mods & (ALL_ACCESS_MODES|STATIC)) == (PROTECTED|STATIC)) {
+                // Apply the special rules for refc here.
+                if (!isRelatedClass(refc, lookupClass))
+                    return isSamePackage(defc, lookupClass);
+                // If refc == defc, the call to isPublicSuperClass will do
+                // the whole job, since in that case refc (as defc) will be
+                // a superclass of the lookup class.
+            }
+        }
+        if (defc == lookupClass)
+            return true;        // easy check; all self-access is OK
+        switch (mods & ALL_ACCESS_MODES) {
+        case PUBLIC:
+            if (refc != defc)  return true;  // already checked above
+            return isClassAccessible(refc, lookupClass);
+        case PROTECTED:
+            return isSamePackage(defc, lookupClass) || isPublicSuperClass(defc, lookupClass);
+        case PACKAGE_ONLY:
+            return isSamePackage(defc, lookupClass);
+        case PRIVATE:
+            // Loosened rules for privates follows access rules for inner classes.
+            return (ALLOW_NESTMATE_ACCESS &&
+                    isSamePackageMember(defc, lookupClass));
+        default:
+            throw new IllegalArgumentException("bad modifiers: "+Modifier.toString(mods));
+        }
+    }
+
+    static boolean isRelatedClass(Class<?> refc, Class<?> lookupClass) {
+        return (refc == lookupClass ||
+                refc.isAssignableFrom(lookupClass) ||
+                lookupClass.isAssignableFrom(refc));
+    }
+
+    static boolean isPublicSuperClass(Class<?> defc, Class<?> lookupClass) {
+        return isPublic(defc.getModifiers()) && defc.isAssignableFrom(lookupClass);
+    }
+
+    /**
+     * Evaluate the JVM linkage rules for access to the given class on behalf of caller.
+     * <h3>JVM Specification, 5.4.4 "Access Control"</h3>
+     * A class or interface C is accessible to a class or interface D
+     * if and only if either of the following conditions are true:<ul>
+     * <li>C is public.
+     * <li>C and D are members of the same runtime package.
+     * </ul>
+     * @param refc the symbolic reference class to which access is being checked (C)
+     * @param lookupClass the class performing the lookup (D)
+     */
+    public static boolean isClassAccessible(Class<?> refc, Class<?> lookupClass) {
+        int mods = refc.getModifiers();
+        if (isPublic(mods))
+            return true;
+        if (isSamePackage(lookupClass, refc))
+            return true;
+        return false;
+    }
+
+    /**
+     * Test if two classes have the same class loader and package qualifier.
+     * @param class1
+     * @param class2
+     * @return whether they are in the same package
+     */
+    public static boolean isSamePackage(Class<?> class1, Class<?> class2) {
+        if (class1 == class2)
+            return true;
+        if (!loadersAreRelated(class1.getClassLoader(), class2.getClassLoader()))
+            return false;
+        String name1 = class1.getName(), name2 = class2.getName();
+        int dot = name1.lastIndexOf('.');
+        if (dot != name2.lastIndexOf('.'))
+            return false;
+        for (int i = 0; i < dot; i++) {
+            if (name1.charAt(i) != name2.charAt(i))
+                return false;
+        }
+        return true;
+    }
+
+    /**
+     * Test if two classes are defined as part of the same package member (top-level class).
+     * If this is true, they can share private access with each other.
+     * @param class1
+     * @param class2
+     * @return whether they are identical or nested together
+     */
+    public static boolean isSamePackageMember(Class<?> class1, Class<?> class2) {
+        if (class1 == class2)
+            return true;
+        if (!isSamePackage(class1, class2))
+            return false;
+        if (getOutermostEnclosingClass(class1) != getOutermostEnclosingClass(class2))
+            return false;
+        return true;
+    }
+
+    private static Class<?> getOutermostEnclosingClass(Class<?> c) {
+        Class<?> pkgmem = c;
+        for (Class<?> enc = c; (enc = enc.getEnclosingClass()) != null; )
+            pkgmem = enc;
+        return pkgmem;
+    }
+
+    private static boolean loadersAreRelated(ClassLoader loader1, ClassLoader loader2) {
+        if (loader1 == loader2 || loader1 == null || loader2 == null) {
+            return true;
+        }
+        for (ClassLoader scan1 = loader1;
+                scan1 != null; scan1 = scan1.getParent()) {
+            if (scan1 == loader2)  return true;
+        }
+        for (ClassLoader scan2 = loader2;
+                scan2 != null; scan2 = scan2.getParent()) {
+            if (scan2 == loader1)  return true;
+        }
+        return false;
+    }
+}