Java command not found

Question

Follow the instruction to setup Java on Ubuntu 11.10 from How do I install Java?.

Running following command to install:

sudo apt-get install openjdk-6-jdk

After it succeeded and I typed "java", it prompts me with this error:

The program 'java' can be found in the following packages:
 * gcj-4.4-jre-headless
 * gcj-4.6-jre-headless
 * openjdk-6-jre-headless
 * gcj-4.5-jre-headless
 * openjdk-7-jre-headless

Answer 1

Did you try this command?

sudo update-alternatives --config java

This will list all the Java versions installed and configured.

If you see one or more installs, it will give you a list each element starting with a number. Just choose the number that corresponds to the version you want to use by default.

If you don't see any installed then something is not right. In that case take a look at this question.

While that question is for Oracle Java 7, it lists methods common to both Java 6 and Java 7, for installing Java and getting Ubuntu to see and link to the new Java installation. If you want version 6, just download the version 6 JDK and follow the instructions provided in that question, changing the filename accordingly.

Answer 2

Solved this by manually setting java path with /etc/profile.

Add following lines to there.

JAVA_HOME=/usr/lib/jvm/java-6-openjdk
export JAVA_HOME
PATH=$PATH:$JAVA_HOME/bin
export PATH

Answer 3

You can fix such types of problem by installing the selected packages:

sudo apt-get install gcj-4.4-jre-headless
sudo apt-get install gcj-4.6-jre-headless
sudo apt-get install openjdk-6-jre-headless
sudo apt-get install gcj-4.5-jre-headless
sudo apt-get install openjdk-7-jre-headless

sudo java -version

I think it works now!