Demonstrate how finalize() methods and shutdownHooks interact
/*
* Copyright (c) Ian F. Darwin, http://www.darwinsys.com/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
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*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
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*
* Java, the Duke mascot, and all variants of Sun's Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun's, and James Gosling's,
* pioneering role in inventing and promulgating (and standardizing) the Java
* language and environment is gratefully acknowledged.
*
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/
/** Demonstrate how finalize() methods and shutdownHooks interact
* with calls to System.exit().
*/
public class ShutdownDemo {
public static void main(String[] args) throws Exception {
// Create an Object with a finalize() method.
Object f = new Object() {
public void finalize() {
System.out.println( "Running finalize()");
}
};
// Add a shutdownHook to the JVM
Runtime.getRuntime().addShutdownHook(new Thread() {
public void run() {
System.out.println("Running Shutdown Hook");
}
});
// Unless the user puts -f (for "free") on the command line,
// call System.exit while holding a reference to
// Object f, which can therefore not be finalized().
if (args.length == 1 && args[0].equals("-f")) {
f = null;
System.gc();
}
System.out.println("Calling System.exit()");
System.exit(0);
}
}
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