Java RPN app for cell phone


Does anyone know of a good RPN calculator app for a Java-capable cell phone?

I'm thinking of getting a Samsung S390G. It's the only phone that supports Tracfone, my carrier, and also does WiFi (as opposed to deducting minutes every time you get or send an email or browse for directions). I use Tracfone because I pay in a year only a little more than most people pay in a month.

The application platform is Java. It's not a touch-screen phone. It looks like a Blackberry, with a small "real" keyboard.

Yeah, I know, I "should" get an iPhone or an Android and use Free42 on it. But then I have to get into contracts, monthly payments and "plan" games with talk minutes vs. bytes of data, and I don't want to go there. Tracfone does what I want in a phone. I figured I can add a few capabilities without it costing me any more.

Thanks for any suggestions!

Edited: 13 Oct 2012, 4:36 p.m. after one or more responses were posted


I use Tracfone because I pay in a month only a little more than most people pay in a year.

That sounds like a spectacularly bad deal. Perhaps you meant the other way around?


Yes I did mean it the other way around. :-) I pay in a year only a little more than most people pay in a month. Hopefully that's a spectacularly *good* deal. I've edited my previous message to fit reality...


Most likely, this phone is a MIDp or BREW based phone. If it were iPhone, Android, Blackberry, or Windows Phone then one of those names would be easily found on the Internet associated this phone's model number. Usually when the OS name is very hard to find, the OS is MIDp or BREW (often listed on the Internet as "proprietary").

I don't know if there are any RPN apps available for this phone. However, as a mobile app developer I can say that MIDp and BREW are painful for developers to develop for and difficult for end-users to find and install applications. Apps that work on one MIDp phone model may not install or work on another (ditto for BREW phone apps). While some of this might have eased up in the last couples years, such phones have few apps available for them if any. Often, these phones are only capable of doing the functionality they shipped with.

In short, there might be a MIDp or BREW calculator app that does RPN. You will have to find out if it is MIDp or BREW based first. If there is an app, then you might be able to install it on the Samsung S390G, but there are no guarantees. Also, there is a remote chance that the phone ships with a calculator built-in that allows for RPN mode (in my experience, this is rare).

I'm not trying to scare you away from this phone; just trying to set expectations.

Good luck.


Thanks, Chris. The stuff I read distictly says the app platform is Java. People are using the usual silly games on it, written in Java. XCalc seems to be available for Java-platform phones of this type, I just don't know if it will work on this specific model.

Supposedly, the S390G is a rebranded Samsung S5270.

Anyway, an RPN calculator app is in the "would be nice" category, not the "must have." The phone has a four-banger calc in it, I'd just have to be careful to enter numbers and operations the "wrong" way round. :-)



Peter, why not find a cheap Android phone and swap the SIM card of your provider into it? Or does the phone use an otherwise unsupported network?

Edit: I've just found a
WikiPedia article which tells that a TracPhone SIM card will require a special phone so you are out of luck.

Edited: 14 Oct 2012, 3:39 p.m.


Yeah, MIDp basically is Java (specifically, it is a defined subset of the desktop Java APIs). The latest versions of BREW also support Java, though I don't know how complete this support is (older BREW phones did not support Java). BlackBerry also supports Java as well, though some of their newest OSes have gone squirrelly enough that I'm not sure whether Java is supported on all models anymore.

Anyways, from looking at the rest of the thread, it looks like some other folks have already answered your original question.


I used to use this Java applet on my phone before I got my iPhone. I thought it worked rather well.


I can also recommend Calc (mentioned by Alex above). Expect some fiddling with input settings because of QWERTY keyboard on your phone.

Just to add to the list - an older and basic is Horse Power. But it has RED LEDs!

Take care


Thanks, Marcus, Alex, and Pavel. One of those apps should work. Maybe I can tweak the code on one of them to use some mnemonic QWERTY keys.

Marcus, as you found, Tracfone only works with "their" phones, so getting a "real" unlocked smartphone won't work. But Tracfone is cheap, and their coverage is good in my area.

Tracfone costs me about $120 per year for 800-1200 minutes, which I don't ever use up. This yearly option is the least expensive way to go. So if this S390G "semi-" smartphone does most of what I can genuinely use, I'll be happy. It has WiFi, and I can always use up some of those surplus minutes for emergency Internet when WiFi is not available.

If that turns out to be not enough, I could move up to Virgin Mobile for about $400/year for a plan with 300 talk minutes/month and unlimited data. They support both Androids and iPhones. Then I'd just use Free42.

Edited: 14 Oct 2012, 5:33 p.m.


Completely off-topic, but Tracfone's ROCK. :-)

I have one as a backup for my Android. I charge it once every nine DAYS, and it does everything this Samsung does except WiFi. I use it when my Android dies, or doesn't make it through the day at an amusement park, and it works perfectly.

I have my Nexus set to no-answer-forward to it, so anyone trying to reach me on my regular phone can get through. It does web browsing if I need it, I can download Java apps (and yes, it's a pain in the butt to do that,), I have all my contacts there, I can take pictures and videos with it, etc.

The phone cost me $29. The service (because it's triple minutes) costs me about $8 a month. And it works better than my Android most of the time.

I don't know why I used to diss Tracfone before, but I think they're awesome now. :-)


Peter, just use your phone for communication and get yourself another device for other purposes! I own an iPod Touch which serves mainly as my music player and has a second use an app platform.


Or even a used/bad esn iPhone 4. That way you can get GPS as well.

Possibly Related Threads…
Thread Author Replies Views Last Post
  HP Prime: =f(x):=expression in spreadsheet app CR Haeger 1 1,715 12-05-2013, 07:53 AM
Last Post: cyrille de Brébisson
  HP PRIME: APP program code DISAPPEARS !! Joseph Ec 0 1,204 11-25-2013, 11:35 AM
Last Post: Joseph Ec
  HP prime: linear solver app Alberto Candel 1 1,444 11-21-2013, 01:57 AM
Last Post: Michael Carey
  HP Prime: Linear Solver app bug BruceH 0 1,154 11-15-2013, 06:36 PM
Last Post: BruceH
  HP Prime - CAS functions in Spreadsheet App CR Haeger 6 2,470 11-11-2013, 12:37 AM
Last Post: Michael de Estrada
  HP Prime - Geometry App inconsistence bluesun08 4 1,809 11-10-2013, 01:48 PM
Last Post: parisse
  HP Prime - Geometry App Intersection bluesun08 2 1,436 11-10-2013, 07:52 AM
Last Post: bluesun08
  HP Prime - more than a spreadsheet app so far CR Haeger 0 1,122 11-08-2013, 03:45 PM
Last Post: CR Haeger
  [PRIME] RPN: another attempt at returning more than one value to the RPN stack Marcus von Cube, Germany 5 2,466 11-05-2013, 02:44 AM
Last Post: Marcus von Cube, Germany
  Equation Library/App for the Prime Harold A Climer 3 1,733 10-30-2013, 10:14 AM
Last Post: CompSystems

Forum Jump: