V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

JNI
       Java Native method Interface (Java, API)


The Free On-line Dictionary of Computing (30 December 2018):

Java Native Interface
JNI

    (JNI) A native programming interface for
   Java that allows Java code running inside a Java Virtual
   Machine to interoperate with applications and libraries
   written in other programming languages such as C, C++ and
   assembly language.

   (1997-12-07)