Alternatives on Ubuntu, when you need to use different versions of a program, like Java

I was deploying an application to the Google App Engine using Java, and I encountered some problems with the version of Java, GAE uses Java EE 5 so you need to compile with at most JDK 7 and I have installed JDK 8 so in order to downgrade without uninstall it. Use alternatives.

I found that Java was installed on /usr/lib/jvm so I download the version that I need from Java web page and unziped it. And it’s a folder like jdk-1.7xxx so move it to /usr/lib/jvm

Now in order to create the alternatives just type the following commands.

sudo update-alternatives --install "/usr/bin/java" "java" "/usr/lib/jvm/jdk1.7.0/bin/java" 1
sudo update-alternatives --install "/usr/bin/javac" "javac" "/usr/lib/jvm/jdk1.7.0/bin/javac" 1
sudo update-alternatives --install "/usr/bin/javaws" "javaws" "/usr/lib/jvm/jdk1.7.0/bin/javaws" 1

Changing the directories for the ones that you already moved to the folder. With this you just said to Ubuntu that he has alternatives to use when someone types the command java, javac or javaws. but it still uses the one that already has, so in order to change that use:

sudo update-alternatives --config java
sudo update-alternatives --config javac
sudo update-alternatives --config javaws

And between each one of the commmands Ubuntu will ask you which one of the implementations you wish to use, type the one you need and that’s all.

Advertisements

One thought on “Alternatives on Ubuntu, when you need to use different versions of a program, like Java

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s