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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

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 *

 * 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).

 *

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 * 2 along with this work; if not, write to the Free Software Foundation,

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/**

 * @test

 * @bug 8198393

 * @summary Instrumentation.retransformClasses(new Class[0]) should be NOP

 * @library /test/lib

 * @modules java.instrument

 * @compile RetransformClassesZeroLength.java

 * @run main RetransformClassesZeroLength

 */

import java.lang.instrument.ClassFileTransformer;

import java.lang.instrument.IllegalClassFormatException;

import java.lang.instrument.Instrumentation;

import java.lang.instrument.UnmodifiableClassException;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.Paths;

import java.security.ProtectionDomain;

import jdk.test.lib.process.ProcessTools;

public class RetransformClassesZeroLength {

    private static String manifest =

            "Premain-Class: " + RetransformClassesZeroLength.Agent.class.getName() + "\n"

            + "Can-Retransform-Classes: true\n";

    private static String CP = System.getProperty("test.classes");

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

        String agentJar = buildAgent();

        ProcessTools.executeProcess(

                ProcessTools.createJavaProcessBuilder(

                        "-javaagent:" + agentJar,

                        "-version")

        ).shouldHaveExitValue(0);

    }

    private static String buildAgent() throws Exception {

        Path jar = Files.createTempFile(Paths.get("."), null, ".jar");

        String jarPath = jar.toAbsolutePath().toString();

        ClassFileInstaller.writeJar(jarPath,

                ClassFileInstaller.Manifest.fromString(manifest),

                RetransformClassesZeroLength.class.getName());

        return jarPath;

    }

    public static class Agent implements ClassFileTransformer {

        public static void premain(String args, Instrumentation inst) {

            inst.addTransformer(new NoOpTransformer());

            try {

                inst.retransformClasses(new Class[0]);

            } catch (UnmodifiableClassException ex) {

                throw new AssertionError(ex);

            }

        }

    }

    private static class NoOpTransformer implements ClassFileTransformer {

        @Override

        public byte[] transform(ClassLoader loader,

                                String className,

                                Class<?> classBeingRedefined,

                                ProtectionDomain protectionDomain,

                                byte[] classfileBuffer

                                ) throws IllegalClassFormatException {

            return null;    // no transform

        }

    }

}