MethodBodyEditor for Java A Java class editor Just Open the desired Java class (File->Open) and then select the desired method from "Methods" tree after that you will see a list with all instructions of selected method. In order to edit instructions double click on instruction or do a right click on the instruction and select from menu "Show Opcode" then simple enter the hexadecimal opcodes of new instructions and click OK. Finally save with File->Save. Added Java 8 new contants pools: http://www.docjar.com/html/api/com/sun/tools/classfile/ConstantPool.java.html Added search member name: File->Search