centOS更换jdk
alternatives --install /usr/bin/java java /usr/share/jdk1.6.0_02/bin/java 300
alternatives --install /usr/bin/javac javac /usr/share/jdk1.6.0_02/bin/javac 300
alternatives --config java
alternatives --install /usr/bin/java java /usr/share/jdk1.6.0_02/bin/java 300
alternatives --install /usr/bin/javac javac /usr/share/jdk1.6.0_02/bin/javac 300
alternatives --config java