diff --git a/src/Java.Interop.Tools.JavaCallableWrappers/Java.Interop.Tools.JavaCallableWrappers/JavaTypeScanner.cs b/src/Java.Interop.Tools.JavaCallableWrappers/Java.Interop.Tools.JavaCallableWrappers/JavaTypeScanner.cs
index 49fc8ca2d..f85427e70 100644
--- a/src/Java.Interop.Tools.JavaCallableWrappers/Java.Interop.Tools.JavaCallableWrappers/JavaTypeScanner.cs
+++ b/src/Java.Interop.Tools.JavaCallableWrappers/Java.Interop.Tools.JavaCallableWrappers/JavaTypeScanner.cs
@@ -50,11 +50,12 @@ public List<TypeDefinition> GetJavaTypes (IEnumerable<string> assemblies, IAssem
 
 		void AddJavaTypes (List<TypeDefinition> javaTypes, TypeDefinition type)
 		{
-			if (type.IsSubclassOf ("Java.Lang.Object", cache) || type.IsSubclassOf ("Java.Lang.Throwable", cache)) {
-
+			if (type.IsSubclassOf ("Java.Lang.Object", cache) ||
+			    		type.IsSubclassOf ("Java.Lang.Throwable", cache) ||
+					(type.IsInterface && type.ImplementsInterface ("Java.Interop.IJavaPeerable", cache))) {
 				// For subclasses of e.g. Android.App.Activity.
 				javaTypes.Add (type);
-			} else if (type.IsClass && !type.IsSubclassOf ("System.Exception", cache) && type.ImplementsInterface ("Android.Runtime.IJavaObject", cache)) {
+			} else if (type.IsClass && !type.IsSubclassOf ("System.Exception", cache) && type.ImplementsInterface ("Android.Runtime.IJa", cache)) {
 				var level   = ErrorOnCustomJavaObject ? TraceLevel.Error : TraceLevel.Warning;
 				var prefix  = ErrorOnCustomJavaObject ? "error" : "warning";
 				Logger (