java ASM

Java ASM
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ASM is a Java bytecode manipulation framework. It can be used to dynamically generate stub classes or other proxy classes,
directly in binary form, or to dynamically modify classes at load time, i.e., just before they are loaded into the Java
Virtual Machine.
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import java.io.FileOutputStream;   
import java.io.PrintStream;   
  
import org.objectweb.asm.ClassWriter;   
import org.objectweb.asm.MethodVisitor;   
import org.objectweb.asm.Opcodes;   
import org.objectweb.asm.Type;   
import org.objectweb.asm.commons.GeneratorAdapter;   
import org.objectweb.asm.commons.Method;   
  
public class Helloworld extends ClassLoader implements Opcodes {   
  
  public static void main(final String args[]) throws Exception {   
  
    // creates a ClassWriter for the Example public class,   
    // which inherits from Object   
  
     ClassWriter cw = new ClassWriter(0);   
     cw.visit(V1_1, ACC_PUBLIC, "Example", null, "java/lang/Object", null);   
     MethodVisitor mw = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null,   
        null);   
     mw.visitVarInsn(ALOAD, 0);