Direct interface primitive vs class

[Ortner]

JNA-Version: 4.5.1
JVM: Oracle 1.8.0_111
Operating System: macOS High Sierra 10.13.3

I have a simple C-Function, that is mapped to Java using direct mapping. The C-Function is defined as:

double JOSim_Base_Test_add(double a, double b);

The working (direct) mapping of this function would be:

    static {
        try {
            Native.register("JOSimBaseLib");
        }catch(Exception e) {
            e.printStackTrace();
        }
    }
    
    //function prototype
    public static native double JOSim_Base_Test_add(double p0, double p1);

But it is also possible to declare the native function in Java with Double:

    static {
        try {
            Native.register("JOSimBaseLib");
        }catch(Exception e) {
            e.printStackTrace();
        }
    }
    
    //function prototype with Double.class
    public static native Double JOSim_Base_Test_add(Double p0, Double p1);

The registration of the method does actually work. It doesn't throw a UnsatisfiedLinkException. The Methods c-peer is found in Native.register(Class<?> cls, NativeLibrary lib) and also put on the registeredClasses map - even though the prototype is incorrect.

Finally, when calling the native method in Java, a NullPointerException is thrown.

Issue

When using direct mapping the register method should throw an UnsatisfiedLinkException, if the native function doesn't match the prototype of the declared function.