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/*
* Copyright (c) 2024, 2025, 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.
*/
import java.lang.classfile.ClassFile;
import java.lang.classfile.MethodModel;
import java.lang.instrument.ClassFileTransformer;
import java.lang.instrument.Instrumentation;
import java.security.ProtectionDomain;
/**
* This agent removes the isHeadless method from java.awt.GraphicsEnvironment.
*/
public class HeadlessMalfunctionAgent {
public static void premain(String agentArgs, Instrumentation inst) {
inst.addTransformer(new ClassFileTransformer() {
@Override
public byte[] transform(ClassLoader loader,
String className,
Class<?> classBeingRedefined,
ProtectionDomain pd,
byte[] cb) {
if (!"java/awt/GraphicsEnvironment".equals(className)) {
return null;
}
System.out.println("Transforming java.awt.GraphicsEnvironment.");
try {
return ClassFile.of().transformClass(ClassFile.of().parse(cb), (classBuilder, element) -> {
if (element instanceof MethodModel method) {
if ("isHeadless".equals(method.methodName().stringValue()) &&
"()Z".equals(method.methodType().stringValue())) {
System.out.println("isHeadless removed from java.awt.GraphicsEnvironment.");
return;
}
}
classBuilder.with(element);
});
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
});
}
}
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