Android and bytecode

[jonahbeckford]

I spent a couple days getting an Android build working: https://gitlab.com/dkml/ext/dkml-jnr#dkml-jnr.

But I ran into a major showstopper ... JNR uses dynamic bytecode classloading:

jnr-ffi/src/main/java/jnr/ffi/provider/jffi/AsmClassLoader.java

Lines 24 to 40 in 0deaac0

	final class AsmClassLoader extends ClassLoader {
	private final ConcurrentMap<String, Class> definedClasses = new ConcurrentHashMap<String, Class>();
	public AsmClassLoader() {
	}
	public AsmClassLoader(ClassLoader parent) {
	super(parent);
	}
	public Class defineClass(String name, byte[] b) {
	Class klass = defineClass(name, b, 0, b.length);
	definedClasses.putIfAbsent(name, klass);
	resolveClass(klass);
	return klass;
	}

Android does not allow bytecode classloading: https://developer.android.com/training/articles/perf-jni.html#unsupported-featuresbackwards-compatibility

Even when I use System.setProperty("jnr.ffi.asm.enabled", "false"); the AsmClassLoader is still used in:

jnr-ffi/src/main/java/jnr/ffi/provider/jffi/ReflectionLibraryLoader.java

Lines 105 to 108 in 0deaac0

	private static final class LazyLoader<T> extends AbstractMap<Method, Invoker> {
	private final DefaultInvokerFactory invokerFactory;
	private final jnr.ffi.Runtime runtime = NativeRuntime.getInstance();
	private final AsmClassLoader classLoader = new AsmClassLoader();

Anyway, I'm going to switch to JNI. If someone wants to continue the ball rolling, they can.