override exist jdk ubuntu

root@CPU10777:/usr/java# update-alternatives --install /usr/bin/java java /usr/java/jdk1.7.0_51_32/bin/java  2
root@CPU10777:/usr/java# update-alternatives --install /usr/bin/javac javac /usr/java/jdk1.7.0_51_32/bin/javac  2
root@CPU10777:/usr/java# update-alternatives --install /usr/bin/javaws javaws /usr/java/jdk1.7.0_51_32/bin/javaws  2

/zserver/java$ sudo mv jdk1.6.0_45/ jdk1.6.0_45_32bit

/zserver/java$ sudo update-alternatives --install "/usr/bin/java" "java" "/zserver/java/jdk1.6.0_45_32bit/bin/java" 1

/zserver/java$ sudo update-alternatives --install "/usr/bin/javac" "javac" "/zserver/java/jdk1.6.0_45_32bit/bin/javac" 1

/zserver/java$ sudo update-alternatives --install "/usr/lib/mozilla/plugins/libjavaplugin.so" "mozilla-javaplugin.so" "/zserver/java/jdk1.6.0_45_32bit/jre/lib/i386/libnpjp2.so" 1

/zserver/java$ sudo update-alternatives --install "/usr/bin/javaws" "javaws" "/zserver/java/jdk1.6.0_45_32bit/bin/javaws" 1

sudo update-alternatives --install "/usr/bin/javaws" "javaws" "/zserver/java/jdk1.6.0_45_32bit/bin/javaws" 1

/zserver/java$ sudo update-alternatives --config java

/zserver/java$ sudo update-alternatives --config javac