When the launcher is first started you’ll notice a small warning in the top right of the pane stating Environment Variable JAVA_HOME cannot be found shown in the image below. The unavailable applications require a Java Run-time Environment to be installed on your system in order to run.
To run these applications you need to install the Oracle Java software. This software can be downloaded from https://java.com/download and will set this environmental variable during installation in most cases. If you have a JRE (or JDK – Java Development Kit) installed already you may only need to set this variable.
Setting the JAVA_HOME variable
In Windows systems
Navigate to: Control Panel -> System -> Advanced System Settings -> Advanced -> Environment Variables…
In the new pane, under either user variables or system variables (depending if multiple users will use your machine) click New.
The variable name should be exactly JAVA_HOME
The location should be that of your JRE directory i.e. C:\Program Files\Java\jdk1.8.0_111
You can confirm the variable by running echo %JAVA_HOME% in command prompt.
The PATH environment variable must also be updated to include %JAVA_HOME%\bin.
In Posix systems
Open terminal, open the file /etc/environment with a text editor like nano or gedit and add the following:
JAVA_HOME=”/usr/lib/jvm/java-7-oracle” ( for example, the actual path of your JRE is likely different. )
Save the file, then load the changes by typing into terminal source /etc/environment
You can check the variable by running echo $JAVA_HOME in terminal.