code: public ConstantInterfaceMethodInfo addConstantInterfaceMethod(String className,
                                                                    String methodName,
                                                                    TypeDesc ret,
                                                                    TypeDesc[] params) {
          
          MethodDesc md = MethodDesc.forArguments(ret, params);
          ConstantInfo ci = new ConstantInterfaceMethodInfo
              (addConstantClass(className), addConstantNameAndType(methodName, md));
          return (ConstantInterfaceMethodInfo)addConstant(ci);
      }
docs: Get or create a constant from the constant pool representing an
  interface method in any interface.