code: public static ExceptionThrower instance(Class<? extends RuntimeException> classType) {
  
          iae.throwIfNull(classType, "The parameter of exception type can not be null.");
          if (classType.equals(IllegalArgumentException.class)) {
              return iae;
          } else {
              iae.throwIfTrue(true, "Not fond ExceptionThrower Utils for :", classType.getClass()
                      .toString());
              return null;
          }
      }
docs: Return specify exception type singleton exceptionThrower.
  
  @param classType
  the exception you want to use to thrower.
  @return an exception thrower instance.