Syndie can be built from source with a modern (1.4+) java development
kit, or with a new GCJ (4.0+).  You must have ant (1.6.5+), and the
source release includes HSQLDB (1.8.0.7), though newer revisions
should work.  You will needs SWT as well - grab the latest version for
your OS and architecture from http://www.eclipse.org/swt/ (or from
your favorite package manager).

First, you need to tell ant where to find SWT - add a line to the
file nbproject/private/private.properies (creating a new directory or
file if necessary):
  swt.dir=../swt-I20061214-1445-gtk-linux-x86
(or whatever the path to the directory containing swt.jar is)

To build a normal java instance, run "ant"

To run it without any installation, run "ant run"

To deploy your modifications into an existing Syndie install, copy
the new ./lib/syndie.jar to the Syndie install's lib/ directory

To build various packages, see the targets and instructions in
doc/web/dev.html