The TogetherSoft acquisition follows the June buyout by Oracle of WebGain's TopLink tools for Java developers.
The TogetherSoft and Oracle deals together leave WebGain with only its Application Composer product, which is also expected to be sold.
TogetherSoft will continue supporting the WebGain products it acquired and will offer users an option to migrate to the TogetherSoft Control package, said spokeswoman Shawn Ramsey.
WebGain Studio consists of the VisualCafe, StructureBuilder, Business Designer and Quality Analyzer products and provides support for the BEA WebLogic Server application server.
The companies did not release details on the cost of the acquisition, but Ramsey said the terms were "financially attractive for TogetherSoft".