|
|||||||||
| PREV CLASS NEXT CLASS | FRAMES NO FRAMES | ||||||||
| SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD | ||||||||
java.lang.Objectjava.lang.Throwable
@TransactionType(value=NOT_SUPPORTED) public class Throwable
The Throwable class is the superclass of all errors and
exceptions in the Java language. Only objects that are instances of this
class (or of one of its subclasses) are thrown by the Java Virtual Machine or
can be thrown by the Java throw statement. Similarly, only
this class or one of its subclasses can be the argument type in a
catch clause.
Instances of two subclasses, Error and
Exception, are conventionally used to indicate that
exceptional situations have occurred. Typically, these instances are freshly
created in the context of the exceptional situation so as to include relevant
information (such as stack trace data).
By convention, class Throwable and its subclasses have two
constructors, one that takes no arguments and one that takes a
String argument that can be used to produce an error message.
A Throwable class contains a snapshot of the execution stack
of its thread at the time it was created. It can also contain a message
string that gives more information about the error.
Here is one example of catching an exception:
try {
int a[] = new int[2];
int b = a[4];
} catch (ArrayIndexOutOfBoundsException e) {
System.out.println("exception: " + e.getMessage());
e.printStackTrace();
}
Direct instances of this class are not bound to any context and can be
passed between contexts without any restrictions. Objects created and returned
by the methods of this class are owned by the caller. In particular, a call to the getMessage()
returns a String instance bound to the owner context of the caller.
See Runtime Environment Specification for the Java Card Platform, Connected Edition, chapter 7 for details regarding transfer of ownership.
| Constructor Summary | |
|---|---|
Throwable()
Constructs a new Throwable with null as its
error message string. |
|
Throwable(String message)
Constructs a new Throwable with the specified error
message. |
|
| Method Summary | |
|---|---|
String |
getMessage()
Returns the error message string of this Throwable object. |
void |
printStackTrace()
Prints this Throwable and its backtrace to the standard
error stream. |
String |
toString()
Returns a short description of this Throwable object. |
| Methods inherited from class java.lang.Object |
|---|
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait |
| Constructor Detail |
|---|
public Throwable()
Throwable with null as its
error message string.
public Throwable(String message)
Throwable with the specified error
message.
message - the error message. The error message is saved for later
retrieval by the getMessage() method.| Method Detail |
|---|
public String getMessage()
Throwable object.
Throwable object
if it was created with an error
message string; or null if it was
created with no error message.public String toString()
Throwable object. If
this Throwable object was
created with an error message string, then the
result is the concatenation of three strings:
getMessage() method for this object
Throwable object was created
with no error message string, then the name of the actual class of this
object is returned.
toString in class ObjectThrowable.public void printStackTrace()
Throwable and its backtrace to the standard
error stream. This method prints a stack trace for this
Throwable object on the error output stream that is the
value of the field System.err. The first line of output
contains the result of the toString() method for this object.
The format of the backtrace information depends on the implementation.
|
|||||||||
| PREV CLASS NEXT CLASS | FRAMES NO FRAMES | ||||||||
| SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD | ||||||||