High-flying Google joined hands yesterday with a former Silicon Valley powerhouse, Sun Microsystems, in a deal that analysts say is designed to attack a common enemy: Microsoft.

On the surface, the deal is a relatively commonplace agreement between two companies to distribute software.

Google’s “toolbar” of applications, with its buttons for search, news, popup-ad blocking, and other features, will be available in downloads of Sun’s Java software. Java is required for certain games and other online interactive features and allows them to work regardless of which device or operating system a consumer is using.

New or updated Java code is downloaded about 20 million times a month, the chief executive of Sun, Scott McNealy, said, so the deal will boost Google’s toolbar distribution as it competes against versions by Microsoft and Yahoo.

Google will pay the struggling Sun for the toolbar download option, as well as buy more Sun hardware and software, though payment terms were not disclosed.

But the agreement “is like an iceberg,” an analyst with Forrester Research, John Rymer, said. “There’s undoubtedly discussions [behind the scenes] … that could be vastly more interesting.”