AS code for calling the ANE:

_context = ExtensionContext.createExtensionContext(EXTENSION_ID, null);

You’ll find that _context is always null. The reason is that the jar was built with JDK 1.7, and the ANE doesn’t support JDK 1.7 well. I used to always use 1.6, so I never noticed.

You need to set JDK 1.6 in the Gradle build:

compileOptions
        {
            targetCompatibility JavaVersion.VERSION_1_6
            sourceCompatibility JavaVersion.VERSION_1_6
        }