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:
Since: JDK1.0, CLDC 1.0
Returns the error message string of this Throwable object.
public void printStackTrace()
Prints this 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
method for this object.
The format of the backtrace information depends on the implementation.
Returns a short description of this Throwable object. If this Throwable object was
with an error message string, then the result is the concatenation of three strings: The name of the actual class of this object ": " (a colon and a space) The result of the
method for this object If this Throwable object was
with no error message string, then the name of the actual class of this object is returned.