How to intall two different versions of same software like operamini, Nimbuzz, (java softwares)

For Example I am using operamini6.1 jar

1. open the jar file with winzip or winrar.

2. Fint the manifest file from the META-INF folder and open it in Notepad (don't close the jar file).

3. Now change the name in (MIDlet-Name:) (MIDlet-Description:) (MIDlet-1:) all should have

same name.

MIDlet-Vendor: Opera Software ASA
MIDlet-Version: 6.1
Nokia-MIDlet-On-Screen-Keypad: no
MIDlet-Permissions-Opt: javax.microedition.io.Connector.sms, javax.wir
eless.messaging.sms.send, javax.microedition.io.Connector.socket, jav
ax.microedition.io.Connector.file.write, javax.microedition.io.Connec
tor.file.read
MIDlet-Name: Opera Mini 6.1.25378
MIDlet-Info-URL: http://mini.opera.com/
Nokia-MIDlet-No-Exit: true
MIDlet-1: Opera Mini 6.1.25378, /i.png, Browser
MicroEdition-Configuration: CLDC-1.0
MIDlet-Icon: /i.png
MIDlet-Description: Opera Mini 6.1.25378
MIDlet-Permissions: javax.microedition.io.Connector.http
MicroEdition-Profile: MIDP-2.0

4. Now save the manifest file and install the jar file. Now It won't replace any version of same software.