Here you will find instructions for installing the Java Development Kit (JDK). This is a manual step that's only required if you're installing a JIRA application from a zip or archive file. If you're using the Windows installer or Linux installer, you don't need to install Java manually. 

Check the Supported platforms page to find which Java versions are supported for JIRA.

Installing Java

You'll need to install the JDK on the same server that will have your JIRA application. 

On Linux and Mac OS X

Before you start, check whether a JDK is already installed. 

1. Open a shell console and type  echo $JAVA_HOME  and hit Enter:
   • If it returns something like /opt/JDK7  or  /usr/lib/jvm/java-7 then your JDK is installed and configured
   • If nothing displays, you'll need to install the JDK or set the $JAVA_HOME  environment variable
2. Check the Supported platforms page to find out which JDK versions are supported for your version of JIRA.
3. Download the appropriate JDK version .
4. Run the Java installer. Detailed installation instructions are provided on http://www.oracle.com/technetwork/java/javase/index-137561.html.
5. Open a shell console and type  echo $JAVA_HOME  and hit Enter to check that it has installed correctly.

On Windows

Before you start, check whether a JDK is already installed.

1. Go to Control Panel > Programs and Features to see what JDK version is installed. 
2. Check the Supported platforms page to find out which JDK versions are supported for your version of JIRA applications.
3. Download the right JDK version.
4. Run the Java installer. Make a note of the installation directory, as you'll need this later.
5. Open a command prompt and type echo %JAVA_HOME% and hit Enter: 
   • If you see a path to your Java installation directory, the JAVA_Home environment variable has been set correctly.
   • If nothing is displayed, or only %JAVA_HOME% is returned, you'll need to set the JAVA_HOME environment variable manually.

Set the JAVA_Home

If you installed the JDK, you'll be setting the  JAVA_HOME  environment variable. If you installed the Java Runtime Environment (JRE), follow the same steps, but set the  JRE_HOME  environment variable instead. 

On Linux

The JAVA_HOME environment variable is sometimes set in the /etc/environment file. You'll need to modify its value to JAVA_HOME="path/to/JAVA_HOME".

1. If JAVA_HOME is not defined in this file, set it using the following command at a shell prompt, when logged in with 'root' level permissions:

   export JAVA_HOME="path/to/JAVA_HOME" >> /etc/environment

2. Log out for these changes to apply.

On Mac OS X

The JAVA_HOME environment variable is set in the ~/.bash_profile file.  You'll need modify its value to JAVA_HOME="path/to/JAVA_HOME".

1. If JAVA_HOME is not defined in this file, set it using the following command at a shell prompt, when logged in with 'root' level permissions:

   export JAVA_HOME="path/to/JAVA_HOME" >> ~/.bash_profile

2. You'll need to open a new terminal for these changes to apply. 

On Windows

1. Locate your Java installation directory, it will be something like  C:\Program Files\Java\jdk1.8.0_65
2. Do one of the following:
   1. Windows 7 – Right click My Computer and select Properties > Advanced
   2. Windows 8 – Go to Control Panel > System > Advanced System Settings
   3. Windows 10 – Search for Environment Variables then select Edit the system environment variables
3. Click the Environment Variables button.
4. Under System Variables, click New.
5. In the Variable Name field, enter:
   • JAVA_HOME if you installed the JDK 
   • JRE_HOME if you installed the JRE 

6. In the Variable Value field, enter your JDK or JRE installation path.

   For Windows users on 64-bit systems:

   Progra~1 = 'Program Files'
   Progra~2 = 'Program Files(x86)'
   

7. Click OK and Apply Changes as prompted.

8. You'll need to close and re-open any command windows that were open before you made these changes. If the changes don't take effect after reopening the command window, restart Windows.

If you start JIRA and you get an error like Windows cannot find '-Xms128m' you've probably not set  JAVA_HOME correctly.