MyClassVisitor.java

package com.example.asm;

import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.FieldVisitor;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;


public class MyClassVisitor extends ClassVisitor {

    public MyClassVisitor(int api, ClassVisitor cv) {
        super(api, cv);
    }
    
    @Override
    public FieldVisitor visitField(int access, String name, String desc, String signature, Object value) {

        String newName = this.remapFieldName(name);
        String newSignature = this.remapFieldSignature(signature);
        
        return super.visitField(access, newName, desc, newSignature, value);
    }

    @Override
    public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
        MethodVisitor superVisitor = super.visitMethod(access, name, desc, signature, exceptions);
        
        return new MethodVisitor(Opcodes.ASM5, superVisitor) {
            
            @Override
            public void visitFieldInsn(int opcode, String owner, String name, String desc) {

                String newName = MyClassVisitor.this.remapFieldName(name);
                String newSignature = MyClassVisitor.this.remapFieldSignature(desc);
                
                super.visitFieldInsn(opcode, owner, newName, newSignature);
            }
            
        };
    }

    protected String remapFieldName(String name) {
        return null; // whatever
    }

    protected String remapFieldSignature(String signature) {
        return null; // whatever
    }

}