code: public static String getMethodDescriptor(final Type returnType,
              final Type... argumentTypes) {
  		StringBuilder sb = new StringBuilder();
          sb.append('(');
          for (int i = 0; i < argumentTypes.length; ++i) {
              argumentTypes[i].getDescriptor(sb);
          }
          sb.append(')');
          returnType.getDescriptor(sb);
          return sb.toString();
      }
docs: Returns the descriptor corresponding to the given argument and return
  types.
  
  @param returnType
  the return type of the method.
  @param argumentTypes
  the argument types of the method.
  @return the descriptor corresponding to the given argument and return
  types.