RedefineDoubleDelete.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
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 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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/*
 * @test
 * @bug 8178870
 * @library /testlibrary
 * @summary Redefine class with CFLH twice to test deleting the cached_class_file
 * @build RedefineClassHelper
 * @run main RedefineClassHelper
 * @run main/othervm -javaagent:redefineagent.jar RedefineDoubleDelete
 */

public class RedefineDoubleDelete {

    // Class gets a redefinition error because it adds a data member
    public static String newB =
                "class RedefineDoubleDelete$B {" +
                "   int count1 = 0;" +
                "}";

    public static String newerB =
                "class RedefineDoubleDelete$B { " +
                "   int faa() { System.out.println(\"baa\"); return 2; }" +
                "}";

    // The ClassFileLoadHook for this class turns foo into faa and prints out faa.
    static class B {
      int faa() { System.out.println("foo"); return 1; }
    }

    public static void main(String args[]) throws Exception {

        B b = new B();
        int val = b.faa();
        if (val != 1) {
            throw new RuntimeException("return value wrong " + val);
        }

        // Redefine B twice to get cached_class_file in both B scratch classes
        try {
            RedefineClassHelper.redefineClass(B.class, newB);
        } catch (java.lang.UnsupportedOperationException e) {
            // this is expected
        }
        try {
            RedefineClassHelper.redefineClass(B.class, newB);
        } catch (java.lang.UnsupportedOperationException e) {
            // this is expected
        }

        // Do a full GC.
        System.gc();

        // Redefine with a compatible class
        RedefineClassHelper.redefineClass(B.class, newerB);
        val = b.faa();
        if (val != 2) {
            throw new RuntimeException("return value wrong " + val);
        }

        // Do another full GC to clean things up.
        System.gc();
    }
}