因?yàn)槁犝fCDT和某個(gè)版本java的沖突問題，換了現(xiàn)在的java 6 u10 beta版. 安裝過程中發(fā)現(xiàn)新增加了一個(gè)quick starter服務(wù)。

狗了一下，發(fā)現(xiàn)這是u10里面的幾個(gè)新特征，旨在增加windows桌面應(yīng)用的啟動(dòng)速度，改善用戶體驗(yàn)。
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啟動(dòng)時(shí)即啟動(dòng)一個(gè)服務(wù)，將jre需要的重要文件預(yù)先裝載入內(nèi)存，這樣java應(yīng)用啟動(dòng)的時(shí)候可以節(jié)約這個(gè)時(shí)間。內(nèi)存消耗不大，20m以內(nèi)。這個(gè)特性可以在控制面板的java console中的高級選項(xiàng)里進(jìn)行開關(guān)。

雖然windows本身也能提供這種預(yù)讀技術(shù)，但是sun自認(rèn)為他們能做的比ms更好，對此也做了解答。

按文檔所言做了下對比測試，沒找到applet，對應(yīng)用的測試則感覺此項(xiàng)服務(wù)開關(guān)時(shí)差距并不明顯，啟動(dòng)速度都比之前版本有提高，可能u10版本整有比較大改善吧。

其實(shí)java 6本身已經(jīng)提供的類似cache機(jī)制已經(jīng)能比較快的啟動(dòng)應(yīng)用了，可以發(fā)現(xiàn)，應(yīng)用在第二次啟動(dòng)的時(shí)候，會(huì)明顯快過第一次。
比如eclipse， 第一次啟動(dòng)40秒，第二次10秒，另外一個(gè)小工具也是5秒到1秒。

sun為此專門設(shè)定了一個(gè)論壇，討論此項(xiàng)技術(shù)，從論壇上看，大部分人對此項(xiàng)技術(shù)的效果持肯定態(tài)度,主要是集中在瀏覽器中的applet體驗(yàn)這塊，不過，現(xiàn)在還有applet么？。


這個(gè)設(shè)計(jì)還是偷梁換柱而已，想起以前sun公司的一個(gè)工程師培訓(xùn)時(shí)說的話，系統(tǒng)的性能關(guān)鍵是你給用戶的感覺，呵呵。u10的另外一個(gè)特性核心安裝也是這個(gè)概念， 把jre切分成若干塊，先安裝核心部分，再延遲安裝其他部分。

目前這項(xiàng)技術(shù)還只能在win2k和xp上使用，未來會(huì)逐步推廣。在我的老本上，jqs會(huì)占用4-5秒的啟動(dòng)時(shí)間，期間有假死跡象。
根據(jù)c&c的原則，未來我們可能也會(huì)看到ms采用類似技術(shù)處理.net。

用戶以后看來還是養(yǎng)成不關(guān)機(jī)的習(xí)慣比較好。

ps 現(xiàn)在也可以在linux下進(jìn)行安裝，參考下文
 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