Sun Microsystems CEO Jonathan Schwartz, an advocate of Web 2.0, announced his resignation on Twitter early Thursday.

He was named CEO in 2006 as Sun encounters a switch in strategic direction away from proprietary systems and toward open source code, including its valued Solaris 10 operating system.

Chairman and co-founder Scott McNealy extended his goodbye last week via a long and emotional memo to employees.

However, both executives were already speculated to quit following the $7.4 billion acquisition by Oracle, which is moving further with plans to integrate Sun into its operations. Last week, at a public meeting, Oracle CEO Larry Ellison vowed to wring more efficiency out of Sun, maintain support for Sun technologies and hire 2,000 new engineers and salespeople.

"Sun was an icon", said Stuart Williams, a senior analyst at Technology Business Research. "It was a small startup that grew to be a billion-dollar player that shaped the course of technology. That's a great story about the U. S. tech industry".

The company's position was wounded with a further hit during the great recession and faced the long regulatory review process, which concluded with approval from the European Union last month.