GVT (Graphic Vector Toolkit) is an object oriented framework that describes complex 2D graphics in terms of a tree of Java objects. GVT is used in Batik to represent how SVG images are to be rendered.
The SVG DOM (Document Object Model) defines the API that programming languages use to interact with SVG documents. There are different 'bindings' of the DOM API for different languages. For example, there is an ECMAScript binding which allows SVG scripts to access or modify SVG documents, for example in reaction to events. There is also a Java technology binding which allows Java programs to dynamically interact with SVG documents. The Java binding and the ECMA Script binding are both available in Batik.
The SVG Generator is a module of Batik that allows Java applications to create SVG content without needing specific knowledge of SVG. Applications doing graphics in Java use an API, embodied by the Graphics2D class, to do all their rendering operations. They use the same code, but different implementations of that API, to render to various outputs such as a screen or a printer. The SVG Generator is another implementation of that API that instead of drawing to a screen or a printer generates SVG content. Because it implements the same API as for printing or drawing to the screen, the same code that does screen rendering and printing can be used with the generator to generate SVG content. For an example of how to use this module, follow this link
The SVG Parser module contains 'micro parsers' specific to SVG to convert SVG specific attributes, such as path data, transforms or color values into equivalent Java objects such as java.awt.geom.GeneralPath, java.awt.geom.AffineTransform or java.awt.Color.