Java语言是一种多用途的语言、并发的语言、以类为基础，面向对象的语言。它的设计尽可能的做到和操作系统是无关的，也就是Java所宣传的那句话：“一次编写，到处运行。”-Java language is a multi-purpose language, concurrent language, to category-based, object-oriented language. It is designed to do as much as possible and is unrelated to the operating system, that is, Java advertises that sentence:　write once, run anywhere.