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Three-year-old SpringSource (née Interface21) has bought 10-year-old Covalent Technologies on undisclosed terms believed to involve stock.

SpringSource, as the company's new name indicates, does work on Spring and Covalent supports 400 users - reportedly including 50% of the Fortune 500 and 20% of the Global 2000 - of the famed Apache Software Foundation's open source projects - the "A" in LAMP - and so - with Sun paying a billion dollars for the "M" in LAMP - it's supposed to be a marriage made in heaven.

They want to be a single source for Spring and its own Spring Framework for Java and stuff like the Apache Tomcat application server and Apache HTTP. Tomcat, they say, is used in production in 64% of enterprises worldwide and Spring is popular with Tomcat users or vice versa and there's shift happening that's pushing people to use the simpler, lighter weight, more modular technologies rather than legacy Java EE that IBM, BEA, Oracle and JBoss peddle - especially JBoss.

Covalent CEO Mark Brewer will become general manager of SpringSource's new Covalent business unit. SpringSource, which claims a thousand customers of its own and wants to be the leading Java open source/middleware house, expects to leverage Covalent's global support.

The joint company is pledged to contribute heavily to open source Apache projects.

Besides commercial Apache support, Covalent, whose founders helped develop the hysterically successful Apache HTTP Web Server, also sell enterprise subscription to its own Enterprise Ready Server, Hyperic HQ monitoring, Terracotta Java clustering and the WSO2 Web Services Application Server.

SpringSource picked up a $10 million A round check from Benchmark Capital last year.