Use Java2SIS (Jar to Sis).
Often, users confuse SIS to JAR with . If your goal is actually to make a Java game run more natively or install seamlessly on a Symbian device, tools like MakeSIS or J2ME MIDlet wrappers take a .jar file and package it inside a .sis installer so the Symbian OS can process it directly. Step-by-Step Guide: Migrating Mobile Assets sis 2 jar converter
: The tool scans the file for compatible resources and UI layouts. Use Java2SIS (Jar to Sis)