Image processing and visualization of medical data has become an essential support for clinical diagnosis and treatment planning. The available open source libraries such as the Insight Registration and Segmentation Toolkit (ITK) and the Visualization Toolkit (VTK) with custom designed user interface can help rapid development of medical imaging applications. Both ITK and VTK are written in C++ language with the wrappers for Tcl, Python, and Java languages. Numbers of researchers and developers implement their proposed algorithms with some reusable functions available in ITK and VTK. The ITK offers extensive image filtering techniques for segmentation and registration applications without support of data visualization, while VTK mainly supports the visualization. Therefore, several medical software systems have been implemented using the connection of ITK and VTK. However, the successful connection has been reported only implementing in C++, Tcl and Python languages. The connection of ITK and VTK using Java language is still a problem. However, Java has the advantages of being a less complex, free, and easily portable programming language. Hence, the ability to connect the ITK and VTK classes directly using Java will benefit the rapid development of medical applications and teaching medical image analysis.