Installers generated by install4j are native executables or shell scripts and can start running without a JRE. However, the installer itself requires a JRE in order to perform its work and so the first action of the installer is to locate a JRE that is suitable for both the installer and your application. In this process it performs the following steps:
Look for a statically bundled JRE. If a statically bundled JRE is included with the installer, it will unpack it and use it. First, this JRE is unpacked to a temporary directory, later it is copied to a location that depends on whether the bundled JRE is configured as shared or not.
Not shared
It is copied to thejre
directory in the installation directory of your application. No other
installer generated by install4j will find this JRE. It will not be made publicly available, for example
in the Windows registry.
Shared
The JRE is copied to the i4j_jres
directory in a common folder which depends on the
operating system:
%CommonProgramFiles%
on Windows, which typically resolves to
C:\Program Files\Common Files
with an English locale.
/opt
if it exists, otherwise /usr/local
on Unix.
If the above folder is not writable, the i4j_jres
directory will be created in the
use home directory and the shared JRE will only be shared for the current user.
Other installers generated by install4j will find this JRE. It will not be made publicly available. For each Java version, only one such JRE can be installed. Shared JREs are never uninstalled.
If no JRE has been found, the installer notifies the user
and offers the following options:
Download a dynamically bundled JRE as configured in the Bundled JRE step of the media wizard.
You can force the installer to skip the first two steps and show this dialog immediately with the
-manual
command line parameter.