1.

2.安装完JDK ，设定环境变量后如果出现这个错误：

[root@localhost lib]# javac

Error occurred during initialization of VM

java/lang/NoClassDefFoundError: java/lang/Object

[root@localhost lib]# java

Error occurred during initialization of VM

java/lang/NoClassDefFoundError: java/lang/Object

解决办法：分别把  

/opt/jdk1.6.0_15/lib/ tools.pack  转为  tools.jar   

 

/opt/jdk1.6.0_15/jre/lib/rt.pack   转为  rt.jar

[root@localhost lib]# pwd

/opt/jdk1.6.0_15/lib

[root@localhost lib]# unpack200 tools.pack tools.jar

[root@localhost lib]# ls

ct.sym  htmlconverter.jar  jconsole.jar  orb.idl     tools.jar   tools.pack.bak

dt.jar  ir.idl             jexec         sa-jdi.jar  tools.pack  visualvm

[root@localhost lib]# pwd

/opt/jdk1.6.0_15/jre/lib

[root@localhost lib]# unpack200 rt.pack rt.jar