Little more than a year has passed and I'm finally able to run java apps on Samsung A737 cell phone.
It not because I spent whole year to figure out, but I just got an USB cable on hand.
The procedure is as follows:
First you need to set the device in the Qualicomm USB mode. There are a lot of info how to do that on the internet. Try to deal *#0523#
Second you need a software, called QPST. It allows you access to phone's file system.
Third, make a .jad file for each .jar file. And you don't have to sign the jar, it's not necessary.
Put the jar/jad pair to a separate folder in /Media/Games
Then you need to backup the system database. Copy /DB2/phonedb/backupDB/PHONEDB.00
to a PC folder. (If something goes wrong, the phone will be probably dead, and restoring the DB is your only way)
Delete the file, then boot the phone.
If everything goes smooth, your application will appear in the UI.