83 lines
2.7 KiB
Java
83 lines
2.7 KiB
Java
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/*
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* Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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class Parent {
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int get() {return 1;}
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}
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class Child extends Parent {
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int get() {return 2;}
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int dummy() {
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// When Child is linked during dynamic dump (when the VM is shutting
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// down), it will be verified, which will recursively cause Child2/Parent2
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// to be loaded and verified.
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// We want to make sure that this is done at a point in the VM lifecycle where
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// it's still safe to do so.
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Parent2 x = new Child2();
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return x.get();
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}
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}
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class Parent2 {
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int get() {return 3;}
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}
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class Child2 extends Parent2 {
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int get() {return 4;}
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}
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class MyShutdown extends Thread{
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public void run(){
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System.out.println("shut down hook invoked...");
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}
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}
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class LinkClassApp {
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public static void main(String args[]) {
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Runtime r=Runtime.getRuntime();
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r.addShutdownHook(new MyShutdown());
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if (args.length > 0 && args[0].equals("run")) {
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System.out.println("test() = " + test());
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} else {
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// Executed during dynamic dumping.
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System.out.println("Test.class is initialized.");
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System.out.println("Parent.class and Child.class are loaded when Test.class is verified,");
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System.out.println("but these two classes are not linked");
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}
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if (args.length > 0 && args[0].equals("callExit")) {
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System.exit(0);
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}
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}
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static int test() {
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// Verification of Test.test() would load Child and Parent, and create a verification constraint that
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// Child must be a subtype of Parent.
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//
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// Child and Parent are not linked until Test.test() is actually executed.
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Parent x = new Child();
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return x.get();
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}
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}
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