java 垃圾回收的陷阱~

//: Garbage.java

// Demonstration of the garbage collector and finalization

class Chair {

	static boolean gcrun = false;

	static boolean f = false;

	static int created = 0;

	static int finalized = 0;

	int i;



	Chair() {

		i = ++created;

		if (created == 47)

			System.out.println("Created 47");

	}



	protected void finalize() {

		if (!gcrun) {

			gcrun = true;

			System.out.println("Beginning to finalize after " + created

					+ " Chairs have been created");

		}

		if (i == 47) {

			System.out.println("Finalizing Chair #47, "

					+ "Setting flag to stop Chair creation");

			f = true;

		}

		finalized++;

		if (finalized >= created)

			System.out.println("All " + finalized + " finalized");

	}

}



public class Garbage {

	public static void main(String[] args) {

		if (args.length == 0) {

			System.err.println("Usage: \n" + "java Garbage before\n or:\n"

					+ "java Garbage after");

			return;

		}

		while (!Chair.f) {

			new Chair();

			new String("To take up space");

		}

		System.out.println("After all Chairs have been created:\n"

				+ "total created = " + Chair.created + ", total finalized = "

				+ Chair.finalized);

		if (args[0].equals("before")) {

			System.out.println("gc():");

			System.gc();

			System.out.println("runFinalization():");

			System.runFinalization();

		}

		System.out.println("bye!");

		if (args[0].equals("after"))

			System.runFinalizersOnExit(true);

	}

} // /:~