Java tutorial
//package com.java2s; /* This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ public class Main { public static boolean mayBeJson(String string) { return !isNullEmptyOrWhitespace(string) && ("null".equals(string) || (string.startsWith("[") && string.endsWith("]")) || (string.startsWith("{") && string.endsWith("}"))); } public static boolean isNullEmptyOrWhitespace(String value) { return value == null || value.isEmpty() || value.trim().isEmpty(); } }