com.sun.org.apache.bcel.internal.generic.ClassGen Java Examples

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Example #1
Source File: Bug8003147Test.java    From openjdk-jdk9 with GNU General Public License v2.0 5 votes vote down vote up
@Test
public void test() throws Exception {
    // Note: com.sun.org.apache.bcel.internal.classfile.JavaClass doesn't
    // support InvokeDynamic, so can't use lambda, also can't use string1 +
    // string2, because javac will generate a dynamic call where invoking
    // string1.concat(string2), so create a separate Bug8003147TestClass
    JAXPTestUtilities.tryRunWithTmpPermission(() -> {
        String classfile = getSystemProperty("test.classes") + "/parsers/Bug8003147TestClass.class";
        JavaClass jc = new ClassParser(classfile).parse();

        // rename class
        ConstantPool cp = jc.getConstantPool();
        int cpIndex = ((ConstantClass) cp.getConstant(jc.getClassNameIndex())).getNameIndex();
        cp.setConstant(cpIndex, new ConstantUtf8("parsers/Bug8003147TestClassPrime"));
        ClassGen gen = new ClassGen(jc);
        Method[] methods = jc.getMethods();
        int index;
        for (index = 0; index < methods.length; index++) {
            if (methods[index].getName().equals("doSomething")) {
                break;
            }
        }
        Method m = methods[index];
        MethodGen mg = new MethodGen(m, gen.getClassName(), gen.getConstantPool());
        gen.replaceMethod(m, mg.getMethod());
        String path = classfile.replace("Bug8003147TestClass", "Bug8003147TestClassPrime");
        gen.getJavaClass().dump(new FileOutputStream(path));

        try {
            Class.forName("parsers.Bug8003147TestClassPrime");
        } catch (ClassFormatError cfe) {
            cfe.printStackTrace();
            Assert.fail("modified version of class does not pass verification");
        }
    }, new FilePermission(getSystemProperty("test.classes") + "/-", "read,write"));
}