import org.objectweb.asm.*;
public class HelloWorldGenerator {
public static void main(String[] args) throws Exception {
ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_FRAMES);
cw.visit(Opcodes.V1_8, Opcodes.ACC_PUBLIC, "HelloWorld", null, "java/lang/Object", null);
MethodVisitor mv = cw.visitMethod(Opcodes.ACC_PUBLIC + Opcodes.ACC_STATIC, "main", "([Ljava/lang/String;)V", null, null);
mv.visitFieldInsn(Opcodes.GETSTATIC, "java/lang/System", "out", "Ljava/io/PrintStream;");
mv.visitLdcInsn("Hello, World!");
mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/io/PrintStream", "println", "(Ljava/lang/String;)V", false);
mv.visitInsn(Opcodes.RETURN);
mv.visitMaxs(0, 0);
mv.visitEnd();
byte[] bytecode = cw.toByteArray();
ClassLoader cl = new ClassLoader() {
public Class<?> defineClass(String name, byte[] bytes) {
return defineClass(name, bytes, 0, bytes.length);
}
};
Class<?> helloWorldClass = cl.defineClass("HelloWorld", bytecode);
helloWorldClass.getMethod("main", String[].class).invoke(null, (Object) new String[] {});
}
}
