Install Oracle JDK over Open JDK on Ubuntu 13.04

• Check your Java version first.

$ java -version

• This will out put you something like below.

java version "1.7.0_25"
OpenJDK Runtime Environment (IcedTea 2.3.10) (7u25-2.3.10-1ubuntu0.13.04.2)
OpenJDK 64-Bit Server VM (build 23.7-b01, mixed mode)

• If so run the given below command as well to verify further what are the jdk components installed.

$ sudo dpkg --list | grep -i jdk

• This will provide show a log like below.

ii  icedtea-7-jre-jamvm:amd64                 7u25-2.3.10-1ubuntu0.13.04.2           amd64        Alternative JVM for OpenJDK,  using JamVM
ii  openjdk-7-jdk:amd64                       7u25-2.3.10-1ubuntu0.13.04.2           amd64        OpenJDK Development Kit (JDK)
ii  openjdk-7-jre:amd64                       7u25-2.3.10-1ubuntu0.13.04.2           amd64        OpenJDK Java runtime, using Hotspot JIT
ii  openjdk-7-jre-headless:amd64              7u25-2.3.10-1ubuntu0.13.04.2           amd64        OpenJDK Java runtime, using Hotspot JIT (headless)
ii  openjdk-7-jre-lib                         7u25-2.3.10-1ubuntu0.13.04.2           all          OpenJDK Java runtime (architecture independent libraries)

• Now you can remove Open JDK as given below.

$ sudo apt-get purge icedtea-* openjdk-*

• Then execute following commands to install Oracle jdk 1.7 on your Ubuntu 13.04

$ sudo apt-get install oracle-java7-installer
$ sudo update-java-alternatives -s java-7-oracle