Installers can be debugged using remote debugging:
java -Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=5005 -jar installer.jar
The above specifies to suspend execution of the installer until the debugger attaches on port 5005.
if the installer requires elevated privileges, it should be run as an administrator.
This is required as the installer relaunches itself if elevated permissions are needed.
You can get a extended log from the installer by setting the java property DEBUG=TRUE
java -DDEBUG=TRUE -jar installer.jar