inputdlg error : HeadlessException

[alxsal]

Hello,
I have an error using the inputdlg function in Octave, and did not find how to 
solve it :

octave:5> prompt={'Width', 'Heigth'};
octave:6> dim=inputdlg(prompt, 'Enter dimensions');
error: [java] java.awt.HeadlessException
error: called from:
error:   /usr/share/octave/packages/java-1.2.8/inputdlg.m at line 98, column 15

octave:6> version
ans = 3.6.2
octave:7> pkg list
Package Name   | Version | Installation directory
---------------+---------+-----------------------
         java *|   1.2.8 | /usr/share/octave/packages/java-1.2.8

I checked the correct installation of the package 
(http://wiki.octave.org/Java_package) :
octave:8> s = javaObject ("java.lang.String", "Hello OctaveString")
s = Hello OctaveString

The same command using matlab (with gui) works fine.

Is my installation of the java package wrong ? I did not understand why the 
java package wiki (http://wiki.octave.org/Java_package) instructs to uninstall 
and reinstall the package. As the final test (with "Hello OctaveString") works, 
I assumed everything was ok and did not uninstall - reinstall.
Any cue as to what I do wrong ?

Alexandre