test/testlibrary_tests/RedefineClassTest.java

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 2 along with this work; if not, write to the Free Software Foundation,
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/*
 * @test
 * @library /test/lib
 * @summary Proof of concept test for RedefineClassHelper
 * @modules java.base/jdk.internal.misc
 * @modules java.compiler
 *          java.instrument
 *          jdk.jartool/sun.tools.jar
 * @run main RedefineClassHelper
 * @run main/othervm -javaagent:redefineagent.jar RedefineClassTest
 */

import static jdk.test.lib.Asserts.*;

/*
 * Proof of concept test for the test utility class RedefineClassHelper
 */
public class RedefineClassTest {

    public static String newClass = "class RedefineClassTest$A { public int Method() { return 2; } }";
    public static void main(String[] args) throws Exception {
        A a = new A();
        assertTrue(a.Method() == 1);
        RedefineClassHelper.redefineClass(A.class, newClass);
        assertTrue(a.Method() == 2);
    }

    static class A {
        public int Method() {
            return 1;
        }
    }
}