Java 5 Update 7 修复了Update 6 的一些bugs，与解决了一些安全问题。
其中一个比较主要的bug是：之前验证签名过的jar非常的慢，并带来性能降低。
关于安全问题，官方提到：
Prior to this update, an applet or application could specify the version of the JRE on which it would run. This has changed. All applets are executed with the latest JRE version. Unsigned Java Web Start applications that specify a version other than the latest trigger a warning, requiring explicit user permission before the application will run. Signed Java Web start applications are not affected
标签：
