Fix ServiceLoader class loader handling in Plugins

Use both the thread context class loader and the interface's own class
loader when discovering plugins via ServiceLoader, deduplicating by class
name. TCCL is consulted first so external implementations can override
built-ins; the interface's class loader is added as a fallback so built-in
implementations are always found even when the TCCL has no visibility into
appose's JAR (e.g. in OSGi containers).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: ctrueden

src/main/java/org/apposed/appose/util/Plugins.java

@@ -34,8 +34,10 @@
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Comparator;
+import java.util.HashSet;
 import java.util.List;
 import java.util.ServiceLoader;
+import java.util.Set;
 import java.util.function.Function;
 import java.util.function.Predicate;
 
@@ -61,9 +63,13 @@ private Plugins() {
 	 * @return List of discovered instances.
 	 */
 	public static <T> List<T> discover(Class<T> iface, Comparator<T> comparator) {
-		ServiceLoader<T> loader = ServiceLoader.load(iface);
 		List<T> singletons = new ArrayList<>();
-		loader.forEach(singletons::add);
+		Set<String> seen = new HashSet<>();
+		for (ClassLoader cl : classLoaders(iface)) {
+			for (T plugin : ServiceLoader.load(iface, cl)) {
+				if (seen.add(plugin.getClass().getName())) singletons.add(plugin);
+			}
+		}
 		if (comparator != null) singletons.sort(comparator);
 		return singletons;
 	}
@@ -75,11 +81,30 @@ public static <T> List<T> discover(Class<T> iface, Comparator<T> comparator) {
 	}
 
 	public static <T, U> @Nullable U create(Class<T> iface, Function<T, U> creator) {
-		ServiceLoader<T> loader = ServiceLoader.load(iface);
-		for (T factory : loader) {
-			U result = creator.apply(factory);
-			if (result != null) return result;
+		Set<String> seen = new HashSet<>();
+		for (ClassLoader cl : classLoaders(iface)) {
+			for (T factory : ServiceLoader.load(iface, cl)) {
+				if (!seen.add(factory.getClass().getName())) continue;
+				U result = creator.apply(factory);
+				if (result != null) return result;
+			}
 		}
 		return null;
 	}
+
+	/**
+	 * Returns the class loaders to consult when discovering plugins.
+	 * The thread context class loader is tried first so that external
+	 * implementations (e.g. in a separate JAR) can override built-ins.
+	 * The interface's own class loader is appended if different, ensuring
+	 * built-in implementations are always found even when the TCCL has no
+	 * visibility into appose's JAR (e.g. in OSGi containers).
+	 */
+	private static <T> List<ClassLoader> classLoaders(Class<T> iface) {
+		List<ClassLoader> loaders = new ArrayList<>();
+		ClassLoader tccl = Thread.currentThread().getContextClassLoader();
+		if (tccl != null) loaders.add(tccl);
+		if (iface.getClassLoader() != tccl) loaders.add(iface.getClassLoader());
+		return loaders;
+	}
 }