FAQ of J2ME Runner


Thanks All for using Android J2ME Runner, a bridge between Android and J2ME world. Here we list most common questions around using our initial public version v1.2.


As an early beta release, we appreciate your patience and tolerance for potential bugs in the application and wish you give us enough feedback so we can make it better in the future.


If you have any suggestions/feedback/questions, please do not hesitate to send email to support@netmite.com.


For example, one good discussion forum can be found at




1.               How do I start?


Looks like this is the top question.


Basically, you give me a J2ME application, we let it run on Android. Many of you may not be aware that a J2ME application is composed of a small file – jad file (xxx.jad) and a larger jar file (xxx.jar). And You just need to feed your own URL to the actual jad file and we try to run for it.


For example, you can enter


in the add/jad text field, and we will automatically create the andriod package file (.apk) and then launch it inside G1.


For starters, you can click those 4 pre-stored links (They are ONLY links to jad file NOT the actual apk file), and you will see it running


Additionally, please refer to our user-guide at



In out next version, we will definitely provide a more user-friendly interface so you can access jad file in Internet more easily.



  1. When I install the J2ME runner, why it asked for accessing my “personal information”?


This is a common misunderstanding. The reason why it shows this message and request this permission is that we had JSR 75 –PIM API implemented.


As a platform, we will NEVER access your own personal information without permission. However, in Android, it is not possible to implement run-time permission check and that’s why we put this permission there.


However, we will also look into other alternatives such as moving permission requirements into individual MIDlet in the future versions.


  1. How to uninstall my applications?


In G1, All MIDlet will becomes a separate application in your phone, so go to Settings/Manage Applications to search and uninstall each applications yourself.


However, due to a BUG in Emulator, in Android Emulator, you can not install/uninstall applications. An alternative is to issue the following commands:

          C:\<your_path_to_android_sdk>\tools\adb shell chmod 777 /data/dalvik-cache


  1. Why sometimes I enter a valid jad url but cannot see it getting installed?


Please check:

  1. whether you have a valid url, copy the url in your browser and see if you can get a real jad to download


  1. check inside jad that there is an entry like MIDlet-Jar-URL:


  1. Each midlet is different and there are some midlets that may using some optional JSR packages which we have NOT yet implemented. We will try to implement it in the future releases.


  1. There are some potential difference between Dalvik byte code vs Java class files, and we will fix it in the upcoming releases.


In other words, if you see Package installer launched, then it means you successfully got .apk and let it install for you.


  1. Why sometimes I see Package installer launched but said: application installed unsuccessfully and the Launch button is disabled?


This is for some users with earlier version of J2ME runner (before 1.2). Actually, this is caused by another bug of android installer system. The reason is our version 1.2 uses a different signature then previous one. But the Android updater was not able to handle it cleanly – it tried to update but failed to uninstall the previous version cleanly and rendering some old data hanging around the system.


To overcome it, what you need to do is to use an old version of  package with old signature, and then perform the following steps:

  1. re-install old version of package 
  2. uninstall old version of package

Now you can install the new versions.


Of course, an alternative is to perform a factory -reset your G1. J

If you have questions, please do not hesitate to contact us and we will happily to provide you access to the old packages.


  1. How to input a character?


Normally, you should be able to enter using your G1 keyboard (or Emulator/PC keyboard). However, in some cases, you may find that the keys you entered does NOT displayed in the correct field. This is mostly caused by the fact that the MIDlet is Trying to intercept the key using the old-fashioned Phone keypad directly.


In typical phone, you donot have QWER keyboard, but the following key layout.


1                  2(abc)           3(def)

4(ghi)            5(jkl)             6(mno)

7(pqrs)         8(tuv)            9(wxuz)

*(.)               0                  #(-+)


So some midlets will “cleverly” intercept those keys and then using # for switching between inputmode: 123 or abc or ABC or symbols.


This is, of course no longer efficient way for entering in QWER keyboard, but unfortunately, since those logics have been long time hard-coded into the actual midlet itself, we have to use their convention (unless they had released a J2ME for QWER version, such as Tmobile sidekick or Blackberry).


To simulate this in J2ME runner, you just need to use the following keys  123456890   only, if you enter other keys, the midlet may get confused – remember to enter *, use ALT-8 and to enter #, use ALT-# from the G1 keyboard.



  1. I lose my network connections……


We have seen reports from users. Some may think it may be related to J2ME runner.


 However, we have not confirm this is a bug related to J2ME runner, because there are various other people seeing the same message


"A network error has occurred. Retry or cancel and return to the pervious screen" in other occasions yesterday.




so please let us know if you consistently seeing this messages after using J2ME runner and does not receive those messages after removing J2ME runner. More detailed information are very helpful.


Another way to test is to turn on WiFi to see if the problem persist. If Not, then probably it is T Mobile’s 3G issue, not ours J


  1. Where can we get converted apk file?


We are working on that, stay tuned. J