IsModifiableClassAgent.java

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
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 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
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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 6331574
 * @summary test isModifiableClass
 * @author Robert Field, Sun Microsystems
 *
 * @run build IsModifiableClassApp IsModifiableClassAgent
 * @run shell MakeJAR3.sh IsModifiableClassAgent 'Can-Retransform-Classes: true'
 * @run main/othervm -javaagent:IsModifiableClassAgent.jar IsModifiableClassApp
 */
import java.lang.instrument.*;

public class IsModifiableClassAgent
{
    public static boolean fail = false;
    public static boolean completed = false;

    public static void
    premain(    String agentArgs,
                Instrumentation instrumentation)
        {
            System.out.println("IsModifiableClassAgent started");

            Class[] allClasses = instrumentation.getAllLoadedClasses();
            int modCount = 0;
            int unmodCount = 0;

            for (int i = 0; i < allClasses.length; i++)
                {
                    Class klass = allClasses[i];
                    boolean isMod = instrumentation.isModifiableClass(klass);
                    if (isMod && klass.isArray()) {
                        System.err.println("Error: array class returned as modifiable: " + klass);
                        fail = true;
                    }
                    if (isMod && klass.isPrimitive()) {
                        System.err.println("Error: primitive class returned as modifiable: " + klass);
                        fail = true;
                    }
                    try {
                        instrumentation.retransformClasses(klass);
                        if (!isMod) {
                            System.err.println("Error: unmodifiable class retransformable: " + klass);
                            fail = true;
                        }
                    } catch (UnmodifiableClassException e) {
                        if (isMod) {
                            System.err.println("Error: modifiable class not retransformable: " + klass);
                            System.err.println("  exception: " + e);
                            fail = true;
                        }
                    } catch (Throwable e) {
                        System.err.println("Error: bad return from retransform: " + klass);
                        System.err.println("  ERROR: " + e);
                        fail = true;
                    }
                    if (isMod) {
                        ++modCount;
                    } else {
                        ++unmodCount;
                    }
                }
            System.out.println("modifiable: " + modCount + ". unmodifiable: " + unmodCount);
            completed = true;
        }
}