Installing Java Wireless Toolkit on Debian Linux
Java ME SDK 3.0 is only available for Mac and Windows.
Linux users can either install Java Wireless Toolkit or try Eclipse Mobile Tools for Java .
This document explains how to install Java Wireless Toolkit .

Since J2ME needs 32 bit Java platform download Java JDK for 32 bit Linux first:
J2SE downloads link

Click on Download button under JDK and accept license agreement.

Download regular tgz file for 32 bit Linux (Linux x86).
Current version is jdk-7u9-linux-i586.tar.gz .
I usually save files to Downloads directory.

You need to login as root .
If you're using Gnome desktop open Root Terminal window ( Applications/Accessories/Root Terminal ).
Otherwise just open a terminal and login as root .
I usually put additional software in /opt directory:

cd /opt
mkdir jdk
cd jdk
mkdir i586
cd i586
cp ~/Downloads/jdk-7u9-linux-i586.tar.gz .
tar xvf jdk-7u9-linux-i586.tar.gz
rm jdk-7u9-linux-i586.tar.gz

This should create new directory: /opt/jdk/i586/jdk1.7.0_09

Fix library dependencies
Log in as root and check if you have apt-file utility installed.
If not you can install it with this command:

apt-get install apt-file

Java Wireless Toolkit depends on the following libraries:

ibXpm (package libxpm-dev)
libXt (package libxt-dev)
libX11 (package libx11-dev)
libICE (package libice-dev)
libSM (package libsm-dev)
libpthread (package libc6-dev)
libm (package libc6-dev)
libnsl (package libc6-dev)
libstdc++6-dev

On older Linux systems (Lenny) you might also need to install ia32-libs package.
Chances are you won't need to install all of those packages since some are installed automatically as a dependency of another.
Install missing packages with apt-get command:

apt-get install libxpm-dev

apt-file is a useful tool for finding which package contains which file.
Use it to find packages containing libXext.so.6 :

apt-file search libXext.so.6

libXext.so.6 is one of the few files that are required by 32 bit JDK libraries.
On Debian Lenny 64 bit running above command yields the following results:

ia32-libs: /emul/ia32-linux/usr/lib/libXext.so.6
ia32-libs: /emul/ia32-linux/usr/lib/libXext.so.6.4.0
libxext6: /usr/lib/libXext.so.6
libxext6: /usr/lib/libXext.so.6.4.0
libxext6-dbg: /usr/lib/debug/usr/lib/libXext.so.6.4.0

If your system already has ia32-libs package installed you're OK.
If not install it with this command (as root user):

apt-get install ia32-libs

Install Wireless Toolkit
Download it from this location:
Java Wireless Toolkit 2.5.2_01
Scroll down until you see blue Download button.

Save sun_java_wireless_toolkit-2.5.2_01-linuxi486.bin.sh to Downloads directory.
You don't have to be logged in as root unless you want to install WTK in directory owned by root user.

I installed WTK in /java directory. Copy downloaded file and make it executable:

cd /java
cp ~/Downloads/sun_java_wireless_toolkit-2.5.2_01-linuxi486.bin.sh .
chmod u+x sun_java_wireless_toolkit-2.5.2_01-linuxi486.bin.sh

Run installation file:

./sun_java_wireless_toolkit-2.5.2_01-linuxi486.bin.sh

When it asks about location of the JDK give it the 32 bit JDK location ( /opt/jdk/i586/jdk1.7.0_09/bin ).
When installation is done you should see directory WTK2.5.2 inside /java .

To test WTK installation go to /java/WTK2.5.2/bin directory and run ktoolbar program.