java.lang
Class Throwable

java.lang.Object
  |
  +--java.lang.Throwable

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

Error, Exception

public class Throwable

extends Object

implements Serializable

This class is the superclass of all classes which can be thrown by the virtual machine. The two direct subclasses represent recoverable exceptions (Exception) and unrecoverable errors (Error). This class provides common methods for accessing a string message which provides extra information about the circumstances in which the throwable was created, and for filling in a walkback (i.e. a record of the call stack at a particular point in time) which can be printed later.

See Also:

Error, Exception, RuntimeException, Serialized Form

Constructor Summary

Throwable()
Constructs a new instance of this class with its walkback filled in.

Throwable(String detailMessage)
Constructs a new instance of this class with its walkback and message filled in.

Throwable(String detailMessage, Throwable throwable)
Constructs a new instance of this class with its walkback, message and cause filled in.

Throwable(Throwable throwable)
Constructs a new instance of this class with its walkback and cause filled in.

Method Summary

Throwable	fillInStackTrace() Record in the receiver a walkback from the point where this message was sent.
Throwable	getCause() Answers the cause of this Throwable, or null if there is no cause.
String	getLocalizedMessage() Answers the extra information message which was provided when the throwable was created.
String	getMessage() Answers the extra information message which was provided when the throwable was created.
StackTraceElement[]	getStackTrace() Answers an array of StackTraceElement.
Throwable	initCause(Throwable throwable) Initialize the cause of the receiver.
void	printStackTrace() Outputs a printable representation of the receiver's walkback on the System.err stream.
void	printStackTrace(PrintStream err) Outputs a printable representation of the receiver's walkback on the stream specified by the argument.
void	printStackTrace(PrintWriter err) Outputs a printable representation of the receiver's walkback on the writer specified by the argument.
void	setStackTrace(StackTraceElement[] trace) Sets the array of StackTraceElements.
String	toString() Answers a string containing a concise, human-readable description of the receiver.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Throwable

public Throwable()

Constructs a new instance of this class with its walkback filled in.

Throwable

public Throwable(String detailMessage)

Constructs a new instance of this class with its walkback and message filled in.

Parameters:

detailMessage - String The detail message for the exception.

Throwable

public Throwable(String detailMessage,
                 Throwable throwable)

Constructs a new instance of this class with its walkback, message and cause filled in.

Parameters:

detailMessage - String The detail message for the exception.

throwable - The cause of this Throwable

Throwable

public Throwable(Throwable throwable)

Constructs a new instance of this class with its walkback and cause filled in.

Parameters:

throwable - The cause of this Throwable

Method Detail

fillInStackTrace

public Throwable fillInStackTrace()

Record in the receiver a walkback from the point where this message was sent. The message is public so that code which catches a throwable and then re-throws it can adjust the walkback to represent the location where the exception was re-thrown.

Returns:

the receiver

getMessage

public String getMessage()

Answers the extra information message which was provided when the throwable was created. If no message was provided at creation time, then answer null.

Returns:

String The receiver's message.

getLocalizedMessage

public String getLocalizedMessage()

Answers the extra information message which was provided when the throwable was created. If no message was provided at creation time, then answer null. Subclasses may override this method to answer localized text for the message.

Returns:

String The receiver's message.

getStackTrace

public StackTraceElement[] getStackTrace()

Answers an array of StackTraceElement. Each StackTraceElement represents a entry on the stack.

Returns:

an array of StackTraceElement representing the stack

setStackTrace

public void setStackTrace(StackTraceElement[] trace)

Sets the array of StackTraceElements. Each StackTraceElement represents a entry on the stack. A copy of this array will be returned by getStackTrace() and printed by printStackTrace().

Parameters:

trace - The array of StackTraceElement

printStackTrace

public void printStackTrace()

Outputs a printable representation of the receiver's walkback on the System.err stream.

printStackTrace

public void printStackTrace(PrintStream err)

Outputs a printable representation of the receiver's walkback on the stream specified by the argument.

Parameters:

err - PrintStream The stream to write the walkback on.

printStackTrace

public void printStackTrace(PrintWriter err)

Outputs a printable representation of the receiver's walkback on the writer specified by the argument.

Parameters:

err - PrintWriter The writer to write the walkback on.

toString

public String toString()

Answers a string containing a concise, human-readable description of the receiver.

Overrides:

toString in class Object

Returns:

String a printable representation for the receiver.

initCause

public Throwable initCause(Throwable throwable)

Initialize the cause of the receiver. The cause cannot be reassigned.

Parameters:

throwable - The cause of this Throwable

Returns:

the receiver.

Throws:

IllegalArgumentException - when the cause is the receiver

IllegalStateException - when the cause has already been initialized

getCause

public Throwable getCause()

Answers the cause of this Throwable, or null if there is no cause.

Returns:

Throwable The receiver's cause.