Small JNI example that

• calls C++ from Java
• calls Java from C++
• calls Java from native thread
• creates instances with parameters
• returns array of custom classes from C to Java
• throws exception in native code
• uses Java wrapper object that owns C++ object to show basic JNI usage.

Does currently only contain a build "script" for Visual Studio, but the files run the same on other platforms if compiled correctly.

• Fix paths in build.bat
• Open the Visual Studio command prompt (watch to run the correct one, 32bit vs 64bit, matching your VM).
• enter repo root directory
• run build.bat

• list functions + signatures of Java class

  javap -s -p {CLASS}

• list object exports (Visual Studio)

  dumpbin.exe /exports {DLL PATH}

• https://docs.oracle.com/javase/8/docs/technotes/guides/jni/spec/jniTOC.html
• http://adamish.com/blog/archives/327
• https://thebreakfastpost.com/2012/01/23/wrapping-a-c-library-with-jni-part-1/
• http://www3.ntu.edu.sg/home/ehchua/programming/java/JavaNativeInterface.html

• RAII wrapper for JNI
  • http://engineering.socialpoint.es/cpp-wrapper-for-jni.html
• Java Exception handling in JNI
  • http://stackoverflow.com/a/2125673
  • http://stackoverflow.com/a/15289742
  • http://www.developer.com/java/data/exception-handling-in-jni.html
• Android JNI tips
  • https://developer.android.com/training/articles/perf-jni.html
• JNI usage in an Eclipse plugin
  • https://www.eclipse.org/forums/index.php/t/97234/
• IBM developerWorks - Java programming with JNI
  • https://www.ibm.com/developerworks/java/tutorials/j-jni/j-jni.html
• Simple method for creating Java Objects in C++
  • http://stackoverflow.com/a/1961432

• Android has multiple classlaoders, so env->FindClass might fail depending on context where it is executed. Have a look at http://stackoverflow.com/a/16302771 (also see comments), and don't forget to make the ClassLoader ref global...
• When calling back into an Android app from a native thread you are on a non-UI thread. Trying to update will fail (just as if called from a Java worker thread). Use runOnUiThread to dispatch "offending" code to UI thread.
• When using JNI in e.g. Tomcat and trying to reload you application, the reload will fail. Tomcat generates a new classloader for each application, but in one VM instance only one classloader may have loaded a particular native lib. See http://stackoverflow.com/a/13242602 for a workaround.