Java is also important in computer science
Increasingly, Java is the language used for important computing paradigms that support applications: object-oriented computing, event-driven computing, distributed objects, linkage to databases, visual/component computing, client/servers, networking, multimedia computing . . .
So Java is an important language to include at an advanced computer science level, along with other languages such as C++, that are useful to students to get jobs.
But the good design features of Java also make it suitable for teaching basic computer science concepts: algorithms, data structures, software design, . . .
- See the (old, but still relevant) discussion by Doug Lea at http://gee.cs.oswego.edu/dl/html/javaInCS.html