Locate Java Runtime
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This action attempts to locate the most suitable Java Runtime Environment (JRE) available on the target system.  It does this by looking at some default paths and environment variables on the system as well as allowing you to specify locations to check.


If the action successfully finds a suitable JRE, the following virtual text variable are set as a result:

<%JavaAvailableVersions%>

A list of the available versions found on the target system before finding the correct one.  Once an acceptable JRE is found, InstallJammer stops looking, so this list will only include up to and including the JRE found that matches our needs.


<%JavaExecutable%>

The full path to the java executable (usually <%JavaHome%>/bin/java).


<%JavaFound%>

True if a Java runtime was found or false if none was found.


<%JavaHome%>

The Java home directory.


<%JavaVersion%>

The version of the Java runtime found. (1.4.2_11, etc...)


<%JavaVersionMajor%>

The major version of the Java runtime found. (1.4, 1.5, etc...)


<%JavaVersionMinor%>

The minor version of the Java runtime found. (1.4.2, 1.6.0, etc...)


<%JavacExecutable%>

The full path to the javac executable if it is found.  If a javac executable is not found, this virtual text will not be set.


<%JavawExecutable%>

The full path to the javaw executable if it is found.  If not found, this variable will point to the main java executable instead.



Standard Properties 

See Standard Action Properties.



Advanced Properties


Maximum Version

This property tells Installjammer the maximum version of the JRE you will accept.


Minimum Version

This property tells InstallJammer the minimum version of the JRE you will accept.


Require JDK

If this property is true, the action will require that a full JDK (Java Development Kit) be installed and not just a JRE (Java Runtime Environment).


Technical Detail

This will make the installer search for the existence of a javac (the Java compiler that is lacking in a JRE installation) binary to determine if the installation is a JDK.


Search Path

This property tells InstallJammer how to search for the JRE.  The value is a list of paths to check for a suitable java installation (separated by ;).


If Default Search Path is included as a path, InstallJammer will use defaults like environment variables and the user's PATH on the target system to try and find the JRE.


Technical Detail

The Default Search Path searches in the following order:


  • JAVA_HOME environment variable
  • JAVAHOME environment variable
  • JDK_HOME environment variable
  • JRE_HOME environment variable
  • JAVA_ROOT environment variable
  • JAVA_BINDIR environment variable
  • PATH environment variable
  • Windows registry (Windows only)
  • Program Files/Java/jre* (Windows only)
  • /usr/java/jdk (UNIX only)
  • /usr/lib/java (UNIX only)
  • /usr/lib/jvm (UNIX only)
  • /usr/lib/jvm/jre (UNIX only)
  • /usr/lib/java-1.4.0 (UNIX only)
  • /usr/lib/java-1.4.1 (UNIX only)
  • /usr/lib/java-1.4.2 (UNIX only)
  • /usr/lib/java-1.5.0 (UNIX only)


If Prompt User is included as a path, InstallJammer will check all of the other paths in order, and upon reaching Prompt User, it will prompt the user asking them to specify the location of the runtime environment.  This is usually best left as the last path so that all of the other directories will be checked before finally prompting the user when no JRE has been found.