Centos下使用yum安装JAVA环境

首先，我们来看看yum库是否有java安装包

[root@233797 www.ctohome.com]yum -y list java*

然后我们安装java1.6.x，怎样使用yum安装java？ 怎么用yum安装jdk？

 
[root@233797 www.ctohome.com]yum -y install  java-1.6.0-openjdk*

查看yum安装java的结果，安装完成后，执行java -version

 
[root@233797 www.ctohome.com]java -version
java version "1.6.0_20"
OpenJDK Runtime Environment (IcedTea6 1.9.10) (rhel-1.23.1.9.10.el5_7-i386)
OpenJDK Client VM (build 19.0-b09, mixed mode)

执行java的时候，遇到错误：

Could not reserve enough space for object heap

Could not create the Java virtual machine.

解决办法：

在ssh下用root执行

  
export _JAVA_OPTIONS="-Xms32m -Xmx64m -XX:MinHeapFreeRatio=20 -XX:MaxHeapFreeRatio=40 -XX:NewSize=10m -XX:MaxNewSize=10m -XX:SurvivorRatio=6 -XX:TargetSurvivorRatio=80 -XX:+CMSClassUnloadingEnabled -XX:+CMSPermGenSweepingEnabled" 

还有错误的话，请参考
http://forums.vpslink.com/linux/1327-java-could-not-reserve-enough-space-object-heap.html

http://forum.openvz.org/index.php?t=msg&goto=7061