Java ‘throw’ Keyword

Exceptions are thrown to signal abnormal conditions that can often be handled by some catcher; though it is possible they may not be caught and therefore could result in a dead thread. Before catching an exception it is must to be thrown first whether by the JVM or by the user itself. So there must be a code somewhere in the program to handle that exception. 

All methods use the throw statement to throw an exception, explicitly within the try block. To throw an exception, the developers use the throw keyword with an object reference as in:

The type of the reference must be derived from the Throwable class or one of its subclasses.

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