1. Java SDK


You have to download the JavaTM 2 Platform, Standard Edition software development kit  
j2sdk-1_4_0-linux-i386-rpm.bin (39 Mo) from :

http://java.sun.com/j2se/1.4/download.html

2. Java Embedded Server


We need the jes-2_0.zip AND the patch jes-2_0_01.zip :

http://wwws.sun.com/software/embeddedserver/buy/

3. Java Packages

We need the comm.jar file from the javacomm Api :

http://java.sun.com/products/javacomm/

And the RXTX library :

http://www.frii.com/~jarvi/rxtx/download.html

Bonus, you have the sources of the x10.jar library from J. Peterson here :

http://www.jpeterson.com/rnd/