Sun\u00a0will release a software development kit in the middle of next year that will allow businesses to customize applications in its open source StarOffice productivity suite to better suit their needs, an executive for the company said Wednesday.Sun's StarOffice Software Developers Kit (SDK) is intended in part to make the productivity suite more competitive with Microsoft's Office suite. It will allow developers to use Java in order to add custom features to the productivity software, by writing software plug-ins or customizing menus, for example, said Joerg Heilig, Sun's director of engineering for StarOffice.Currently, StarOffice developers can tweak the software using a scripting language called StarOffice Basic, which is similar to Microsoft's Visual Basic language, he said."There are things you can actually do in StarOffice 6.0 already, it's just the development kit wasn't available," Heilig said. Some resources for StarOffice developers are available at OpenOffice.org, an open source community that develops a free version of StarOffice.Microsoft Office developers have long used tools to customize the Redmond, Washington, company's software suite for specific business uses. For example, a developer can create macros within Microsoft Excel that automate steps for filling out expense reports, such as currency conversion.Sun's goal is to let developers create similar macros with Java, taking advantage of its widespread use by developers."We believe this is a big advantage because many people know Java," Heilig said. Additionally, "the security model and design principles of Java can be very easily used and reused in the context of an office suite."The toolkit will be available as a download from the OpenOffice.org Web site in the middle of next year, Sun said. It will also be included with the next minor upgrade to StarOffice 6.0, due in the same timeframe. That planned release is being designed primarily for enterprise customers, according to Heilig.An early version of the SDK is currently available on the OpenOffice.org\u00a0Web site.