Installing Java can be a pain in the ass. You have to download the files manually for licensing purposes 
cd /usr/ports/java/diablo-jdk15
make install clean
You’ll see the notes regarding downloading the files. Access the urls with a browser, accept the agreements and download the two files it wants.
Note: you need an account at Sun.com for one of the files - a further pain in the ass.
diablo-caffe-freebsd5-i386-1.5.0_07-b01.tar.bz2 is the source, tzupdater-1_3_0-2007h.zip is the timezone update.
When that’s done, move them into your /usr/ports/distfiles directory.
cd /usr/ports/java/diablo-jdk15
make install clean
This time you should see the farmiliar port install config page. Make sure the timezone update is selected and continue.
Take a break, this takes a while. When it’s done, test it out by typing:
rehash
java -version
and you should see something similar to this:
Java(TM) 2 Runtime Environment, Standard Edition (build diablo-1.5.0-b01)
Java HotSpot(TM) Client VM (build diablo-1.5.0_07-b01, mixed mode)