[Java.Interop] Review Critical and High Gendarme reports (#196)

Checked and handled the Gendarme reports labeled with
**Severity: Critical** and **Severity: High** in `make fxcop` output.

In one case refactored the `JniRuntime.RaisePendingException()` method
to reuse code by calling `JniEnvironment.Exceptions.Throw()`.

Author: radekdoulik

gendarme-ignore.txt

@@ -532,6 +532,8 @@ M: Java.Interop.JniObjectReferenceType Java.Interop.JniEnvironment/References::G
 M: Java.Interop.JniObjectReference Java.Interop.JniEnvironment/Reflection::ToReflectedMethod(Java.Interop.JniObjectReference,Java.Interop.JniMethodInfo,System.Boolean)
 M: Java.Interop.JniObjectReference Java.Interop.JniEnvironment/Reflection::ToReflectedField(Java.Interop.JniObjectReference,Java.Interop.JniFieldInfo,System.Boolean)
 M: Java.Interop.JniObjectReferenceFlags Java.Interop.JniObjectReference::get_Flags()
+# This method is used in Java.Interop.GenericMarshaler.dll, the internals are visible to this assembly. Looks like gendarme doesn't know InternalsVisibleTo attribute.
+M: Java.Interop.JniObjectReference Java.Interop.JniPeerMembers/JniInstanceMethods::AllocObject(System.Type)
 
 # I think Gendarme is buggy here; `JavaArray<T>.CheckLength(IList<T>)` *is* used.
 M: System.Int32 Java.Interop.JavaArray`1::CheckLength(System.Collections.Generic.IList`1<T>)
@@ -557,3 +559,12 @@ R: Gendarme.Rules.Performance.UseTypeEmptyTypesRule
 # The PCL profile we're using doen't *have* Type.EmptyTypes!
 M: System.Void Java.Interop.JniRuntime/JniTypeManager::.cctor()
 
+R: Gendarme.Rules.BadPractice.CheckNewExceptionWithoutThrowingRule
+# This method constructs JavaException and calls ToString () on it. We only care about Java stack trace here, so we don't need to throw the exception to get managed StackTrace.
+M: System.Exception Java.Interop.ManagedPeer::CreateJniLocationException()
+# This method uses a JavaException and passes its PeerReference property along. We don't want to throw that property.
+M: System.Void Java.Interop.JniEnvironment/Exceptions::Throw(System.Exception)
+
+R: Gendarme.Rules.Correctness.DisposableFieldsShouldBeDisposedRule
+# We call Dispose on marshalMemberBuilder field in the JniRuntime::Dispose method. Looks like gendarme bug, it doesn't handle well the `?.` operator.
+T: Java.Interop.JniRuntime

src/Java.Interop/Java.Interop/JniEnvironment.Errors.cs

@@ -32,7 +32,7 @@ public static void ThrowNew (JniObjectReference klass, string message)
 			public static void Throw (Exception e)
 			{
 				if (e == null)
-					throw new ArgumentNullException ("e");
+					throw new ArgumentNullException (nameof (e));
 				var je = e as JavaException;
 				if (je == null) {
 					je  = new JavaProxyThrowable (e);

src/Java.Interop/Java.Interop/JniRuntime.cs

@@ -414,16 +414,12 @@ partial class JniRuntime {
 
 		public virtual void RaisePendingException (Exception pendingException)
 		{
+#if XA_INTEGRATION
 			if (pendingException == null)
 				throw new ArgumentNullException (nameof (pendingException));
-#if XA_INTEGRATION
 			throw new NotSupportedException ("Do not know how to marshal System.Exception instances.");
-#else   // XA_INTEGRATION
-			var je  = pendingException as JavaException;
-			if (je == null) {
-				je  = new JavaProxyThrowable (pendingException);
-			}
-			JniEnvironment.Exceptions.Throw (je.PeerReference);
+#else   // !XA_INTEGRATION
+			JniEnvironment.Exceptions.Throw (pendingException);
 #endif  // !XA_INTEGRATION
 		}
 	}