src/main/java/org/plumelib/bcelutil/InstructionListUtils.java
protected final void insert_at_method_start(MethodGen mg, InstructionList new_il) {

    // Ignore methods with no instructions
    InstructionList il = mg.getInstructionList();
    if (il == null) {
      return;
    }
    insert_before_handle(mg, il.getStart(), new_il, false);
  }
protected final void insert_at_method_start(MethodGen mg, InstructionList new_il) {

    // Ignore methods with no instructions
    InstructionList il = mg.getInstructionList();
    if (il == null) {
      return;
    }
    insert_before_handle(mg, il.getStart(), new_il, false);
  }
Inserts an instruction list at the beginning of a method.

@param mg MethodGen of method to be modified
@param new_il InstructionList holding the new code