因为听说CDT和某个版本java的冲突问题，换了现在的java 6 u10 beta版. 安装过程中发现新增加了一个quick starter服务。

狗了一下，发现这是u10里面的几个新特征，旨在增加windows桌面应用的启动速度，改善用户体验。
When JQS is fully enabled, there will be a new Windows Service running called "Java Quick Starter". In TaskManager, the new JQS service is running as "jqs.exe". JQS improves initial startup time for applets and applications by reducing the disk I/O required. This is achieved by periodically prefetching some of the most heavily used Java Runtime Environment files into memory (occupying no more than 20Mb of RAM). Later, when Java is launched, much less disk I/O is required which makes startup much snappier and noticeably faster.

亦即在windows启动时即启动一个服务，将jre需要的重要文件预先装载入内存，这样java应用启动的时候可以节约这个时间。内存消耗不大，20m以内。这个特性可以在控制面板的java console中的高级选项里进行开关。

虽然windows本身也能提供这种预读技术，但是sun自认为他们能做的比ms更好，对此也做了解答。

按文档所言做了下对比测试，没找到applet，对应用的测试则感觉此项服务开关时差距并不明显，启动速度都比之前版本有提高，可能u10版本整有比较大改善吧。

其实java 6本身已经提供的类似cache机制已经能比较快的启动应用了，可以发现，应用在第二次启动的时候，会明显快过第一次。
比如eclipse， 第一次启动40秒，第二次10秒，另外一个小工具也是5秒到1秒。

sun为此专门设定了一个论坛，讨论此项技术，从论坛上看，大部分人对此项技术的效果持肯定态度,主要是集中在浏览器中的applet体验这块，不过，现在还有applet么？。


这个设计还是偷梁换柱而已，想起以前sun公司的一个工程师培训时说的话，系统的性能关键是你给用户的感觉，呵呵。u10的另外一个特性核心安装也是这个概念， 把jre切分成若干块，先安装核心部分，再延迟安装其他部分。

目前这项技术还只能在win2k和xp上使用，未来会逐步推广。在我的老本上，jqs会占用4-5秒的启动时间，期间有假死迹象。
根据c&c的原则，未来我们可能也会看到ms采用类似技术处理.net。

用户以后看来还是养成不关机的习惯比较好。

ps 现在也可以在linux下进行安装，参考下文
 Jacek

This is *not* true. I have installed update N on two Ubuntu installations and it runs without problems.

It appears that the packaging did not include an _installer_ for Linux. What you get is a directory (for me, the JDK directory), which you then need to link in to your browser. See http://forums.java.net/jive/thread.jspa?threadID=31412&tstart=0

It's not much effort for a developer and I expect a proper installer is forthcoming.

I've already spent quite a few hours testing applets using Firefox on Ubuntu Feisty. No problems, great performance. I think they can still improve but this is a big step forward.

This is a _packaging_ issue. Please try and run some manual tests yourself before posting a news item like this on JL. It will likely spread to blogs and other news sites and take days to quiet down.

The focus now, I think, should be on testing the new release and providing feedback. There is a list of forums to post to on the download page