Ah, the irony.

Fresh off its failed attempt to prove that Google's Android operating system infringed on its Java patents, as first reported by GigaOm, Oracle has sued a small company called Lodsys, complaining that the Texas-based outfit has been harassing its customers with questionable claims of patent infringement.

"Lodsys has repeatedly threatened numerous Oracle customers with assertion of the Patents-in-Suit against Oracle’s Web Commerce Products," Oracle's suit read (.pdf). "Lodsys is not entitled to any royalties from Oracle or any of its customers, nor does Oracle or any of its customers need a license to the Patents-in-Suit."

Lodsys has made a name for itself in recent years with its efforts to pressure independent iOS and Android application developers into paying licenses fees for use of four patents it owns. A year ago, it sued a group of small developers in the patent-friendly Eastern District of Texas.

In bizarre fashion, it told the developers that if its claims were wrong, it would pay them $1,000 apiece.

Apparently, Lodsys is also going after Oracle customers. The database giant says that its suit is an attempt to disarm Lodsys so that it will stop harassing Oracle's customers with letters, phone calls and emails about obtaining a license to its four patents.

Walgreens and REI, among other Oracle customers, were recently named as defendants in a suit brought by Lodsys.

Oracle drew scorn for its claims that Google infringed on two of its Java patents in building Android, and in the end, a jury shot down the claims.

In the suit against Lodsys, Oracle filed eight claims against four patents: U.S. patents 5,999,908, 7,133,834, 7,222,078 and 7,620,565.

Lodsys can best be described as a shell company, saying on its homepage that these four patents are the core of its business. The company does not make any products but says that its goal is to "embrace and empower invention by supporting an Innovative Economy" by licensing its patents.