应用程序安全是一个综合性的课题，它需要在权衡各方面的因素之后，再作出安全策略。首先分析了Java平台自身的安全机制，括它的安全策略、认证和授权，之后分析Java应用程序中的一些缺陷和不足，并提出相应的改进方法。-Application security is a comprehensive subject, it needs to weigh the various factors, the re-make security policy. First analysis of the Java platform' s own security mechanisms, including its security policies, authentication and authorization, after analyzing some Java application flaws and shortcomings, and propose an improved method.