The software and hardware maker offered no details of the lawsuit and Eastman Kodak has yet to disclose details of its case, which was made in a New York district court, according to a statement from Sun.
Kodak could not be reached for comment.
The lawsuit apparently came after several months of talks between the two companies.
"Based on discussions over many months with Kodak, Sun believes that this suit is without merit, and, accordingly, will defend itself vigorously and is confident that it will prevail," Sun said.
Launched by Sun in 1995, the Java programming language is not tied to a particular processor or platform and so has wide support across a range of machines. Today it can run on products as diverse as personal computers, mobile phone handsets, video game consoles and personal digital assistants.
Kodak has worked with Sun on several aspects of Java.
The company was one of six key developers to work with Sun in the creation of the Java Advanced Imaging application programming interface (API), which allows image processing to be incorporated into Java, and other work has included contributions to the development of the Java 2D API, which provides better support for continuous tone images.