Eclipse exiting before it really starts.

I am failing to start Eclipse on Ubuntu Dapper 6.06.

$sudo apt-cache policy eclipse
eclipse:
  Installed: 3.1.2-1ubuntu6
  Candidate: 3.1.2-1ubuntu6
  Version table:
 *** 3.1.2-1ubuntu6 0
        500 http://archive.ubuntu.com dapper/universe Packages
        100 /var/lib/dpkg/status

When I try to to start, it exits with the following error:

JVM terminated. Exit code=1
/usr/lib/jvm/java-gcj/bin/java
-Djava.library.path=/usr/lib/jni
-Dgnu.gcj.precompiled.db.path=/var/lib/gcj-4.1/classmap.db
-Dgnu.gcj.runtime.VMClassLoader.library_control=never
-Dosgi.locking=none
-jar /usr/share/eclipse/startup.jar
-os linux
-ws gtk
-arch x86
-launcher /usr/lib/eclipse/eclipse
-name Eclipse
-showsplash 600
-exitdata 13d10017
-install /usr/share/eclipse
-vm /usr/lib/jvm/java-gcj/bin/java
-vmargs
-Djava.library.path=/usr/lib/jni
-Dgnu.gcj.precompiled.db.path=/var/lib/gcj-4.1/classmap.db
-Dgnu.gcj.runtime.VMClassLoader.library_control=never
-Dosgi.locking=none
-jar /usr/share/eclipse/startup.jar

If I then close the error dialog, I am left with the splash, and doing a "ps -ef | grep eclipse" gives me the command (trimming all the other junk, parent pid is 1)

"/usr/lib/eclipse/eclipse -name Eclipse -showsplash 600 /usr/share/eclipse/plugins/org.eclipse.platform_3.1.2/splash.bmp"

Which I have to "kill -9" to remove. It takes a fair time before it shows the error message, and shows a taskbar task and a progress bar up until then.

Info on my gcj packages:

apt-cache policy java-gcj-compat
java-gcj-compat:
  Installed: 1.0.56-0ubuntu1
  Candidate: 1.0.56-0ubuntu1
  Version table:
 *** 1.0.56-0ubuntu1 0
        500 http://archive.ubuntu.com dapper/main Packages
        100 /var/lib/dpkg/status

I note that Eclipse is being very specific about which JVM it uses, and not trusting the /etc/alternatives/java to find its VM.

Does anybody have any ideas how to solve it and what might be going wrong?