n JDK 和 OpenJDK 的区别

http://hi.baidu.com/openware/blog/item/19e501ddaae8581a632798bd.html



Frans Thamura wrote:> anyone have a list that compare Sun JDK with OpenJDK and also OpenJDK> JRE with "Sun JREThere is no OpenJDK JRE, specifically. The comparison that makes senseis one betweenSun Java SE 6 JDK and the OpenJDK jdk6 project.Differences are:a) licenses:OpenJDK jdk6 is Free Software, Sun's Java SE 6 JDK downloads are not, inparticular because* they contain proprietary third party components (also known as'encumbrancies'), that wouldn't be trivial to rip and replace in astable release series* they contain Sun's own proprietary code that has not been / could notbe opened up so farb) deployment code:OpenJDK does not have a plugin or a webstart implementation.The code Sun has in the deployment area has been largely rewritten forJava SE 6 update 10, and the new code,being a significant chunk of software, requires a new run through thebusiness decision making process on Sun's side.Meanwhile, the IcedTea project augments the OpenJDK jdk6 project withindependent implementationsof the plugin and webstart, called gcjwebplugin and netx. Thoseindependent implementations have a differentset of strengths and weaknesses from Sun's implementations: they work on64 bit Linux, for example, a platformthat hasn't been supported by Sun's own plugin yet. On the other hand,gcjwebplugin currently lacks anadequate Java-JavaScript integration that's required by some applets toexecute as well as expected.c) bundled code:Sun's Java SE 6 download comes with a lot of (third party) softwarebundled in, for exampleJava DB, Rhino, Visual VM, etc. OpenJDK jdk 6 project leaves suchsoftware out as much as possible,concentrating on the necessities required for a compatibleimplementation of Java SE 6.IcedTea augments OpenJDK jdk6 with Rhino, though there is still work tobe done on making the integration seamless.There is also some initial work on integrating VisualVM into IcedTea.d) encumbered code:The Java SE 6 JDK still mostly contains the ~4 % of encumbered, i.e.third party code that couldn't be licensed asFree Software, and  was replaced by open source implementations from thecommunity in OpenJDK 6.cheers,dalibor topic

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