Java: Handling Java Installation on Debian/Ubuntu

Table of Contents

Scenario

Suppose that you try to start an Eclipse installation, and it fails returning exit code 8, 13, etc. , something like “java terminated exit code 8“.

This is usually caused due to the version of Java used by the environment that it is incompatible with the version of the Eclipse installation.

Another situation comes to happen when the available java is that you wish.

THE FLASH SOLUTION

If you like things very fast, here is the summary (or follow below the detailed information):

– installs or fix cmds:
sudo apt-get install default-jdk
sudo update-alternatives –config java
sudo apt-get purge default-jdk

– reboot if necessary

– check with:
sudo apt-get install default-jdk
java -version
whereis java

How to handle java’s environment?

We shall think about two situations.

We may have no java installed or not.

If you have already install java, go to “SET AND RESET JAVA ENV” section.

DISCOVERING YOUR ENVIRONMENT

Type:

java -version

Check if there are other alternatives:

sudo update-alternatives –config java

There is only one alternative in link group java (providing /usr/bin/java): /usr/lib/jvm/java-11-openjdk-amd64/bin/java
Nothing to configure.
update-alternatives: warning: forcing reinstallation of alternative /usr/lib/jvm/java-11-openjdk-amd64/bin/java because link group java is broken
update-alternatives: warning: not replacing /usr/bin/java with a link

This output shows just one option, but If there are more options will return the a list.

INSTALLING FRESH JAVA

At least three options:

Using apt, the default installation method on Debian distributions.
Manually, by download of a tar file.
If a framework like Eclipse, you may download it with an installer.

Using apt (apt-get) command

The apt command usually installs the Open-JDK java.
Command:
sudo apt-get install default-jdk

Sometimes it is necessary to use Oracle’s versions due to compatibilities issues.
I usually install them manually, but it may be used apt-get when you add the source into /etc/apt/sources.list.
In these cases, the documentation will lead you.
I rarely use this.

Manual installation

A very good solution and very flexible. Easy and fast that enables to work with many different types.
Download the tar file and extract its content.
Move its content to another directory, other than the “Download” dir.
Create the command to use that version. For instance:

nano myCmd
“$JAVA_PATH/bin/java” -jar myApp.jar

chmod 775 myCmd

To run:
./myCmd

Framework With Installer

The installer will do everything.
Just follow the instructions.

SET AND RESET JAVA ENV

Here comes when things get more interesting and where the issues happen.

The tools to discover your java env:

Which installation is working to run “java” command:
java -version

When you have no idea where the installations may be:
whereis java

Which options do the environment have?
sudo update-alternatives –config java

#SWITCHING THE ENVIRONMENT’S JAVA VERSION

When the comand

sudo update-alternatives –config java

works, it is easy. Just get the option you desire.

#MANUAL SWITCH

Sometimes, the environment has some issue and things don’t go as you expect requiring some radical procedures, they are:

Install the default java, even though you do not wish it.

sudo apt-get install default-jdk

Test using the commands:
java -version
sudo update-alternatives –config java

The 1st cmd must return the same version as default and the second shall show at least one option.

WHEN THINGS DON’T HAPPEN AND HOW TO FIX

Uninstall the default java previously installed:

sudo apt-get purge default-jdk

sudo apt update

Force removing the java appointment:

sudo rm /usr/bin/java

Reinstall java default:

sudo apt-get install default-jdk

Retest.
If it fails, try one more.
If it still fails, reboot the system and repeat the installation and uninstallation procedures and reboot again.

If successful, you shall get this:

sudo ls -al /usr/bin/java
lrwxrwxrwx 1 root root 22 Jan 5 19:45 /usr/bin/java -> /etc/alternatives/java

sudo ls -al /etc/alternatives/java
lrwxrwxrwx 1 root root 43 Jan 5 19:45 /etc/alternatives/java -> /usr/lib/jvm/java-11-openjdk-amd64/bin/java

Well, and if still fails, there is still one workaround.
Use the absolut path to call java. Ex.:

JAVA_HOME/bin/java -version

NOTE:

WRONG: this way doesn’t work:

ln -s /home/portables_d/jdk1.6.0_30_64/bin/java java630
java630 -version

Returns:

java630 -version
java630: error while loading shared libraries: libjli.so: cannot open shared object file: No such file or directory
alsdias@vmvd20 $ /home/portables_d/jdk1.6.0_30_64/bin/java -java

RIGHT: this way works:

/home/portables_d/jdk1.6.0_30_64/bin/java -version