Ubuntu replaces sun jdk with the default open jdk

Ubuntu replaces sun jdk with the default open jdk 1. download the installation package to the official website: jdk-7-linux-i586.tar.gz2. create the installation directory: sudo mkdir/usr/lib/jvm3. decompress: tar zxvf. /jdk-7-linux-i586.tar.gz-C/usr/lib/jvm4. set environment variable: vim ~ /. Bashrc export JAVA_HOME =/usr/lib/jvm/jdk-7 export CLASSPATH =.: $ {JAVA_HOME}/lib :$ {JRE_HOME}/lib export PATH =$ {JAVA_HOME}/bin: $ PATH to close the terminal, reopen sudo update-alternatives -- install/usr/bin/java/usr/lib/jvm/jdk-7/bin/java 300 sudo update-alternatives -- install/usr/bin/javac javac/usr/lib/jvm/jdk-7/bin/javac 300 sudo update-alternatives -- config java display: select path priority status ready * 0/usr/lib/jvm/java-6-openjdk/jre/bin/java 1061 automatic mode 1/usr/lib/jvm/java-6-openjdk/jre/bin/java 1061 manual mode 2/usr/lib/jvm/java-6-sun/jre/bin/java 63 enter the selected number in manual mode: 2 press ENTER 4. verify that the java-version has been changed to sun's jre