安装完JDK ，设定环境变量后出现这个错误：

[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