libswt is just the SWT from the Eclipse project, repackaged so that it can be easily built into a native "so" on Linux (and possibly other OS's which can build GTK and GCJ).
SWT stands for Standard Widget Toolkit. The Eclipse project built this graphical toolkit because they didn't want to use Swing, which is Sun's solution for GUI Java code.
- cp libswt-gtk2-2.1.1-3.tar.gz /tmp
- cd /tmp/
- tar xvzf libswt-gtk2-2.1.1-3.tar.gz
- cd libswt-gtk2-2.1.1-3
- make clean
- make install