Agile2D is a framework that provides a nearly complete implementation of Java2D built using the industry standard OpenGL API.
dxflib is an opensource C++ library for reading and writing AutoCAD (R) DXF files. It provides the functionality to read and write many basic entities as well as information about layers and blocks. From the author of QCAD.
Form4j is a java package to handle interactive GUI Forms for Java (Swing) Clients. Data and Form Definitions are XML based. Primary Purpose: Forms for Java Clients in an XML Environment.
Set of tools and libs for managing structured data in a very flexible way: Imp./Exp. ASCII, XML, SQL, PS, Tex/LaTex, RTF GUI: X-Windows, MS-Windows Interface to C++, DBs, Perl, PHP, Java, TCP/IP LISP-like interpreter written in C++ using C-LIB
jLug is a virtual Lego(tm) modeller developed for any platform supporting Java & Java3D.
Partykewl is a performance oriented particle library for video games that comes with an nice visual editor.
wxArt2D gives wxWindows applications sophisticated vector drawing functionality. It is based on a framework supporting multiple views within a hierarchical document. Supports drawing & (Graph) editing. In-output in SVG, GDSII, XML, easy to extend.