The next step after preverification is to package your application. MIDlet suite packaging involves two entities:
a Java archive file of the MIDlet files
an optional application descriptor file
Although you can choose to optionally package J2SE applications for deployment, the MIDP specification requires that you package MIDlet suites using the Java archive (JAR) utility. In fact, the MIDP specification requires that all MIDlet suites be delivered to devices in a compressed JAR file format. Normally, servers that support delivery of MIDlet suites to devices store MIDlet suite files in compressed JAR format. Either the server or the entity that uploads the file to the server creates the compressed JAR file.
A JAR archive of a MIDlet suite ...