java exception trace

Question

When i execute the below code,I am seeing the output as:

Finally

Exception in thread "main" java.lang.NullPointerException at ClientTestConcepts.main(ClientTestConcepts.java:9)

Who prints the bold faced statements.

public class ClientTestConcepts {
    public static void main(String []args){
        try{
            throw new NullPointerException();
        }
        finally{
            System.out.println("Finally");
        }
    }
}

Answer 1

The Java runtime.

It catches all exceptions not handled in user code, and prints them on the error output (by default).

Answer 2

Each thread has a default uncaught exception handler that runs when an exception makes it to the top of the stack. The one you are observing is provided by ThreadGroup.uncaughtException:

Called by the Java Virtual Machine when a thread in this thread group stops because of an uncaught exception, and the thread does not have a specific Thread.UncaughtExceptionHandler installed.

The uncaughtException method of ThreadGroup does the following: (...)
... a message containing the thread's name, as returned from the thread's getName method, and a stack backtrace, using the Throwable's printStackTrace method, is printed to the standard error stream.

If you want some other behaviour register an uncaught exception handler for the thread.