Complete support for IPv6 on Windows XP (SP1) and 2003 server has been provided in this release. (4608529)
The networking API now provides a way of setting timeouts on connect and read operations for protocol handlers. This will benefit any HTTP client application that must behave robustly in the event of server failure. (4700777)
A new API provides a mean for Java applications, which includes RMI applications, to be launched via inetd. (4295885, 4673940)
The InetAddress class now provides an API to allow testing for the reachability of a host. This features provides a ping-like capability in Java. (4639861)
Cookie support has been improved. Applications and web containers can provide Cookie management by implementing the newCookieHandler API. (4696506)
Proxy server configuration has been improved. It can now be dynamic and controlable by web containers and applications through the ProxySelector API, which can also handle failures to connect to the proxy. (4696512)
A new framework provides a way for protocol handlers to access a file caching mechanism implemented by the platform or by a third party. (4837267)
The specification of the URL class now mandates a minimum set of URL protocol handlers that are guaranteed to be present in Java SE. They are http, https, file, jar and ftp. (4180636)
There have been a number of enhancements for JSSE (SSL/TLS). For more information, please see: Java SE 5 Security Enhancements
