On Windows, when an installer is executed it always generates a log file in the temp directory that contains
information about the JRE search sequence and can be used for debugging purposes. The name of the log file
i4j_nlog_. If you have a problem
with JRE detection or the installer startup, please send this log file along with your support request.
It is also possible to generate this log for the JRE detection of the generated Windows launchers.
In order to switch on logging, please define the environment variable
INSTALL4J_LOG=yes and look for the newest text file whose name starts with
i4j_nlog_ in the temp directory. This is done silently, without notifying the user and
is also suitable for situations where launchers are called automatically or repeatedly.
An easier way for a user to create a log file is to start the launcher with the
/create-i4j-log argument. The launcher will notify the user where the log is created and
will offer to open an explorer window with the log file selected. After the message box, the launcher will
continue to start up.
Similar to Windows, macOS launchers also support the
environment variable definition for debug logging. Rather than writing a log file, they write to the
system log. You can display the system log by starting the "Console" application which is located
Setting the environment variable can be done by opening a terminal and executing
launchctl setenv INSTALL4J_LOG=yes
Then all newly started applications in the Finder will have this environment variable set. The current terminal will not have it set until you quit the Terminal application and start it again.
Rather than setting the environment variable for all install4j launchers, you can set it for a particular
invocation only. To do that, call the
the application bundle and prefix the call with the definition of the environment variable. For an application
bundle "MyApp.app", the call looks like this:
In this case, the log output will also be written to the terminal. Using
will not work with this technique, since the latter gets the environment variables from the Finder.
Note that logging only works for GUI launchers and not for command line and service launchers which are implemented as Unix shell scripts. Also, launchers for the Apple JRE (Java 6) do not support logging. There is no command line argument that activates logging, like on Windows.
If an exception is thrown in the installer, it prepares an error log and informs the user about its location
You can force the installer to print exceptions to stderr for debugging purposes with the
-Dinstall4j.debug=true command line option.
Additionally, all installers and uninstaller generate an installation log that can be used for
debugging purposes. After a successful installation it is located in
For uninstallation or if the end of the installation cannot be reached, you can find it in your temp directory if
-Dinstall4j.keepLog=true to the installer or uninstaller. The file is prefixed
If you would like the installer to log to stderr as well, you can pass
-Dinstall4j.logToStderr=true to the
installer. Both arguments can also be useful for debug installers and uninstallers, where they have to be passed as VM parameters.
You can define the error handling for every installation or uninstallation action separately. Please find more information in the Screens and Actions help topic.
The process of an installer returns
0 if the installation was completed successfully,
1 if the installation fails and
83 if the installer could not find
a suitable JVM to run. These exit codes are especially useful to check the result of an
unattended installer run.