6915171: Clarify checked/unchecked status of Throwable and its subclasses
Reviewed-by: dholmes
--- a/jdk/src/share/classes/java/lang/Error.java Thu Jan 07 08:14:48 2010 -0800
+++ b/jdk/src/share/classes/java/lang/Error.java Thu Jan 07 19:42:43 2010 -0800
@@ -26,27 +26,31 @@
package java.lang;
/**
- * An <code>Error</code> is a subclass of <code>Throwable</code>
+ * An {@code Error} is a subclass of {@code Throwable}
* that indicates serious problems that a reasonable application
* should not try to catch. Most such errors are abnormal conditions.
- * The <code>ThreadDeath</code> error, though a "normal" condition,
- * is also a subclass of <code>Error</code> because most applications
+ * The {@code ThreadDeath} error, though a "normal" condition,
+ * is also a subclass of {@code Error} because most applications
* should not try to catch it.
* <p>
- * A method is not required to declare in its <code>throws</code>
- * clause any subclasses of <code>Error</code> that might be thrown
+ * A method is not required to declare in its {@code throws}
+ * clause any subclasses of {@code Error} that might be thrown
* during the execution of the method but not caught, since these
* errors are abnormal conditions that should never occur.
*
+ * That is, {@code Error} and its subclasses are regarded as unchecked
+ * exceptions for the purposes of compile-time checking of exceptions.
+ *
* @author Frank Yellin
* @see java.lang.ThreadDeath
+ * @jls3 11.2 Compile-Time Checking of Exceptions
* @since JDK1.0
*/
public class Error extends Throwable {
static final long serialVersionUID = 4980196508277280342L;
/**
- * Constructs a new error with <code>null</code> as its detail message.
+ * Constructs a new error with {@code null} as its detail message.
* The cause is not initialized, and may subsequently be initialized by a
* call to {@link #initCause}.
*/
@@ -69,7 +73,7 @@
/**
* Constructs a new error with the specified detail message and
* cause. <p>Note that the detail message associated with
- * <code>cause</code> is <i>not</i> automatically incorporated in
+ * {@code cause} is <i>not</i> automatically incorporated in
* this error's detail message.
*
* @param message the detail message (which is saved for later retrieval
--- a/jdk/src/share/classes/java/lang/Exception.java Thu Jan 07 08:14:48 2010 -0800
+++ b/jdk/src/share/classes/java/lang/Exception.java Thu Jan 07 19:42:43 2010 -0800
@@ -26,19 +26,27 @@
package java.lang;
/**
- * The class <code>Exception</code> and its subclasses are a form of
- * <code>Throwable</code> that indicates conditions that a reasonable
+ * The class {@code Exception} and its subclasses are a form of
+ * {@code Throwable} that indicates conditions that a reasonable
* application might want to catch.
*
+ * <p>The class {@code Exception} and any subclasses that are not also
+ * subclasses of {@link RuntimeException} are <em>checked
+ * exceptions</em>. Checked exceptions need to be declared in a
+ * method or constructor's {@code throws} clause if they can be thrown
+ * by the execution of the method or constructor and propagate outside
+ * the method or constructor boundary.
+ *
* @author Frank Yellin
* @see java.lang.Error
+ * @jls3 11.2 Compile-Time Checking of Exceptions
* @since JDK1.0
*/
public class Exception extends Throwable {
static final long serialVersionUID = -3387516993124229948L;
/**
- * Constructs a new exception with <code>null</code> as its detail message.
+ * Constructs a new exception with {@code null} as its detail message.
* The cause is not initialized, and may subsequently be initialized by a
* call to {@link #initCause}.
*/
@@ -61,7 +69,7 @@
/**
* Constructs a new exception with the specified detail message and
* cause. <p>Note that the detail message associated with
- * <code>cause</code> is <i>not</i> automatically incorporated in
+ * {@code cause} is <i>not</i> automatically incorporated in
* this exception's detail message.
*
* @param message the detail message (which is saved for later retrieval
--- a/jdk/src/share/classes/java/lang/RuntimeException.java Thu Jan 07 08:14:48 2010 -0800
+++ b/jdk/src/share/classes/java/lang/RuntimeException.java Thu Jan 07 19:42:43 2010 -0800
@@ -26,22 +26,24 @@
package java.lang;
/**
- * <code>RuntimeException</code> is the superclass of those
+ * {@code RuntimeException} is the superclass of those
* exceptions that can be thrown during the normal operation of the
* Java Virtual Machine.
- * <p>
- * A method is not required to declare in its <code>throws</code>
- * clause any subclasses of <code>RuntimeException</code> that might
- * be thrown during the execution of the method but not caught.
*
+ * <p>{@code RuntimeException} and its subclasses are <em>unchecked
+ * exceptions</em>. Unchecked exceptions do <em>not</em> need to be
+ * declared in a method or constructor's {@code throws} clause if they
+ * can be thrown by the execution of the method or constructor and
+ * propagate outside the method or constructor boundary.
*
* @author Frank Yellin
+ * @jls3 11.2 Compile-Time Checking of Exceptions
* @since JDK1.0
*/
public class RuntimeException extends Exception {
static final long serialVersionUID = -7034897190745766939L;
- /** Constructs a new runtime exception with <code>null</code> as its
+ /** Constructs a new runtime exception with {@code null} as its
* detail message. The cause is not initialized, and may subsequently be
* initialized by a call to {@link #initCause}.
*/
@@ -63,7 +65,7 @@
/**
* Constructs a new runtime exception with the specified detail message and
* cause. <p>Note that the detail message associated with
- * <code>cause</code> is <i>not</i> automatically incorporated in
+ * {@code cause} is <i>not</i> automatically incorporated in
* this runtime exception's detail message.
*
* @param message the detail message (which is saved for later retrieval
--- a/jdk/src/share/classes/java/lang/Throwable.java Thu Jan 07 08:14:48 2010 -0800
+++ b/jdk/src/share/classes/java/lang/Throwable.java Thu Jan 07 19:42:43 2010 -0800
@@ -34,6 +34,11 @@
* this class or one of its subclasses can be the argument type in a
* <code>catch</code> clause.
*
+ * For the purposes of compile-time checking of exceptions, {@code
+ * Throwable} and any subclass of {@code Throwable} that is not also a
+ * subclass of either {@link RuntimeException} or {@link Error} are
+ * regarded as checked exceptions.
+ *
* <p>Instances of two subclasses, {@link java.lang.Error} and
* {@link java.lang.Exception}, are conventionally used to indicate
* that exceptional situations have occurred. Typically, these instances
@@ -142,6 +147,7 @@
* @author unascribed
* @author Josh Bloch (Added exception chaining and programmatic access to
* stack trace in 1.4.)
+ * @jls3 11.2 Compile-Time Checking of Exceptions
* @since JDK1.0
*/
public class Throwable implements Serializable {