Nokia 3310: MIDlet always gives "Can't compile the file"

Question

After reading this comment proving that it's possible to write custom apps for the new Nokia 3310 3G (TA-1006), I'm trying to get my own app running.

After doing a lot of reading about what MIDP, CLDC etc. are, I installed the Java ME SDK (on a fresh Ubuntu installation since Oracle only supports that or Windows), Eclipse and the Sun Wireless toolkit.

First of, I couldn't find any information on which version of MIDP and CLDC are supported by the device, so I went ahead and tried a few possible permutations, these are my results:

CLDC \ MIDP | 1.0 | 2.0 | 2.1 |
1.0         |  *  |  *  |  X  |
1.1         |  *  |  *  |  ?  |
1.8         |  X  |  X  |  ?  |

The ? ones I have not tried since MIDP 2.1 does not work and there is nothing to be gained and the X ones give an error "Can't install [MIDlet name] because it doesn't work with this phone".

So it seems like the phone supports the MIDP 2.0 profile and CLDC 1.1 configurations, however when I try to install my app (with any of the configurations of *) it always goes like this:

1. "[MIDlet name] is untrusted. Continue anyway?" > Ok (this was expected)
2. "Can't compile the file" (here is where I'm stuck)

What I tried so far (besides the various version permutations)

• Initially I tried with a very basic MIDlet subtype:

public void startApp()
{
    Form form = new Form("Hello");
    form.append(new StringItem("Hello", "World!");
    Display.getDisplay(this).setCurrent(form);
}

• Next, I tried using these templates provided by the Eclipse plugin:
  • Splash MIDlet Template
  • Hello World Midlet Template
• When selecting the runtime configuration (always picked DefaultColorPhone) I adjusted the version profile from MIDP-2.1 to MIDP-2.0
• Tried the other configs MediaControlSkin and QwertyDevice

I always produced the *.jar and .jad files by clicking the "Packaging > Create Package" button in the "Application Descriptor" view.

At some point it became experimenting with various settings which I didn't have much confidence that it'll work, reading up and rinse-repeat. When looking for alternatives, the whole journey became quite frustrating since a lot of links are either on dodgy websites, 404s or for the old 3310 phone.

TL;DR

What configuration and build steps are necessary to get a simple (unsigned) application compiled for the new Nokia 3310?

---

Here are the full contents of the simplest failing example which imo should work:

$ tree
.
├── Application Descriptor
├── bin
│   └── com
│       └── stackoverflow
│           └── kvn
│               └── test
│                   └── SOExample.class
├── build.properties
├── deployed
│   └── DefaultColorPhoneM2.0
│       ├── SOTest.jad
│       └── SOTest.jar
├── res
└── src
    └── com
        └── stackoverflow
            └── kvn
                └── test
                    └── SOExample.java

13 directories, 6 files
$ cat Application\ Descriptor 
MIDlet-1: SOExample,,com.stackoverflow.kvn.test.SOExample
MIDlet-Jar-URL: SOTest.jar
MIDlet-Name: SOTest MIDlet Suite
MIDlet-Vendor: MIDlet Suite Vendor
MIDlet-Version: 1.0.0
MicroEdition-Configuration: CLDC-1.1
MicroEdition-Profile: MIDP-2.0
$ cat build.properties 
# MTJ Build Properties
DefaultColorPhoneM2.0.includes=src/com/stackoverflow/kvn/test/SOExample.java\

DefaultColorPhoneM2.0.excludes=\

$ cat src/com/stackoverflow/kvn/test/SOExample.java 
package com.stackoverflow.kvn.test;

import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;

public class SOExample extends MIDlet {

    private Form form;

    protected void destroyApp(boolean unconditional)
        throws MIDletStateChangeException { /* nop */ }

    protected void pauseApp() { /* nop */ }

    protected void startApp() throws MIDletStateChangeException {
        form = new Form("Hello");
        form.append(new StringItem("Hello", "World!"));
        Display.getDisplay(this).setCurrent(form);
    }
}

_{Software info of the device: Model: TA-1006; Software: 15.0.0.17.00; OS version: MOCOR_W17.44.3_Release; Firmware number: sc7701_barphone}