There are several ways to access native libraries from Java the most common so far is JNI.

Instead of using JNI it is possible to use automatic briding code.

Automatic Bridging

no native code compiling required

• Java Native Access (JNA) (licensed under the LGPL)
• NLink
• J/Direct (not available anymore)

JNI Generators

this tools build the jni code for you based a simplified input file.

• SWIG

Unclassified

com4j, JNative, jnieasy, , NoodleGlue, JNIWrapper