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Java example source code file (RedefineClassesDisabledTest.java)

This example Java source code file (RedefineClassesDisabledTest.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

asimpleinstrumentationtestcase, atestcasescaffold, can, classdefinition, exampleredefine, file, fileinputstream, inputstream, redefineclassesdisabledtest, reflection, string, throwable, unsupportedoperationexception

The RedefineClassesDisabledTest.java Java example source code

/*
 * Copyright (c) 2004, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/**
 * @test
 * @bug 4882798
 * @summary test that redefineClasses and isRedefineClassesSupported behave correctly when redefine is not enabled
 * @author Robert Field, Sun Microsystems -- as modified from the work of Gabriel Adauto, Wily Technology
 *
 * @run build RedefineClassesDisabledTest
 * @run shell RedefineSetUp.sh
 * @run shell MakeJAR.sh basicAgent
 * @run main/othervm -javaagent:basicAgent.jar RedefineClassesDisabledTest RedefineClassesDisabledTest
 */

import java.io.*;
import java.lang.instrument.*;
import java.lang.reflect.*;
public class
RedefineClassesDisabledTest
    extends ASimpleInstrumentationTestCase
{

    /**
     * Constructor for RedefineClassesDisabledTest.
     * @param name
     */
    public RedefineClassesDisabledTest(String name)
    {
        super(name);
    }

    public static void
    main (String[] args)
        throws Throwable {
        ATestCaseScaffold   test = new RedefineClassesDisabledTest(args[0]);
        test.runTest();
    }

    protected final void
    doRunTest()
        throws Throwable {
        testIsRedefineClassesSupported();
        testSimpleRedefineClasses();
    }


    public void
    testIsRedefineClassesSupported()
    {
        boolean canRedef = fInst.isRedefineClassesSupported();
        assertTrue("Can redefine classes flag set incorrectly (true)", !canRedef);
    }

    public void
    testSimpleRedefineClasses()
        throws Throwable
    {
        // first load the class and prove that it is the right one
        ExampleRedefine ex = new ExampleRedefine();

        // with this version of the class, doSomething is a nop
        int firstGet = ex.get();
        ex.doSomething();
        int secondGet = ex.get();

        assertEquals(firstGet, secondGet);

        // now redefine the class. This will change doSomething to be an increment

        // this class is stored in a different place (scratch directory) to avoid collisions
        File f = new File("Different_ExampleRedefine.class");
        System.out.println("Reading test class from " + f);
        InputStream redefineStream = new FileInputStream(f);

        byte[] redefineBuffer = NamedBuffer.loadBufferFromStream(redefineStream);

        ClassDefinition redefineParamBlock = new ClassDefinition(   ExampleRedefine.class,
                                                                    redefineBuffer);

        // test that the redefine fails with an UnsupportedOperationException
        boolean caught = false;
        try {
            fInst.redefineClasses(new ClassDefinition[] {redefineParamBlock});
        } catch (UnsupportedOperationException uoe) {
            caught = true;
        }
        assertTrue(caught);
    }

}

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