[runtime] Extend JNI remapping for R8

Documentation/docs-mobile/TOC.yml

@@ -262,6 +262,8 @@
         href: messages/xa1035.md
       - name: XA1036
         href: messages/xa1036.md
+      - name: XA1037
+        href: messages/xa1037.md
       - name: XA1038
         href: messages/xa1038.md
       - name: XA1042

Documentation/docs-mobile/messages/index.md

@@ -147,6 +147,7 @@ or 'Help->Report a Problem' in Visual Studio for Mac.
 + [XA1035](xa1035.md): The 'BundleAssemblies' property is deprecated and it has no effect on the application build. Equivalent functionality is implemented by the 'AndroidUseAssemblyStore' and 'AndroidEnableAssemblyCompression' properties.
 + [XA1036](xa1036.md): AndroidManifest.xml //uses-sdk/@android:minSdkVersion '29' does not match the $(SupportedOSPlatformVersion) value '21' in the project file (if there is no $(SupportedOSPlatformVersion) value in the project file, then a default value has been assumed).
 Either change the value in the AndroidManifest.xml to match the $(SupportedOSPlatformVersion) value, or remove the value in the AndroidManifest.xml (and add a $(SupportedOSPlatformVersion) value to the project file if it doesn't already exist).
++ [XA1037](xa1037.md): Unsupported @(Reference) item: {item}
 + [XA1038](xa1038.md): The '{0}' MSBuild property has an invalid value. Value values are {1}.
 + [XA1039](xa1039.md): The Android Support libraries are not supported in .NET 9 and later, please migrate to AndroidX. See https://aka.ms/xamarin/androidx for more details.
 + [XA1040](xa1040.md): The NativeAOT runtime on Android is an experimental feature and not yet suitable for production use. File issues at: https://github.com/dotnet/android/issues

Documentation/docs-mobile/messages/xa1037.md

@@ -0,0 +1,25 @@
+---
+title: .NET for Android error XA1037
+description: XA1037 error code
+ms.date: 09/16/2026
+f1_keywords:
+  - "XA1037"
+---
+
+# .NET for Android error XA1037
+
+## Example messages
+
+```
+error XA1037: Unsupported @(Reference) item: {item}
+```
+
+## Issue
+
+The specified `@(Reference)` item is not a supported Java archive or source
+directory.
+
+## Solution
+
+Update the `@(Reference)` item to reference a `.jar` file, an `.aar` file, or
+a Java source directory.

external/Java.Interop/src/Java.Interop/Java.Interop/JniFieldInfo.cs

@@ -10,6 +10,8 @@ public sealed class JniFieldInfo
 
 		public      bool        IsStatic    {get; private set;}
 
+		internal    JniType?    StaticRedirect;
+
 		internal    bool        IsValid {
 			get {return ID != IntPtr.Zero;}
 		}
@@ -70,4 +72,3 @@ public override string ToString ()
 		}
 	}
 }
-

external/Java.Interop/src/Java.Interop/Java.Interop/JniMethodInfo.cs

@@ -1,6 +1,7 @@
 #nullable enable
 
 using System;
+using System.Runtime.InteropServices;
 
 namespace Java.Interop
 {
@@ -19,19 +20,20 @@ internal    bool    IsValid {
 
 #if DEBUG
 		string? name, signature;
+		IntPtr nameUtf8, signatureUtf8;
 #endif  // !DEBUG
 
 		public      string  Name {
 #if DEBUG
-			get => name ?? throw new NotSupportedException ();
+			get => name ??= GetUtf8String (nameUtf8);
 #else   // !DEBUG
 			get => throw new NotSupportedException ();
 #endif  // !DEBUG
 		}
 
 		public      string  Signature {
 #if DEBUG
-			get => signature ?? throw new NotSupportedException ();
+			get => signature ??= GetUtf8String (signatureUtf8);
 #else   // !DEBUG
 			get => throw new NotSupportedException ();
 #endif  // !DEBUG
@@ -55,11 +57,54 @@ public JniMethodInfo (string name, string signature, IntPtr methodID, bool isSta
 #endif  // DEBUG
 		}
 
+		internal JniMethodInfo (IntPtr nameUtf8, string signature, IntPtr methodID, bool isStatic)
+		{
+			ID              = methodID;
+			IsStatic        = isStatic;
+
+#if DEBUG
+			this.nameUtf8   = nameUtf8;
+			this.signature  = signature;
+#endif  // DEBUG
+		}
+
+		internal JniMethodInfo (IntPtr nameUtf8, IntPtr signatureUtf8, IntPtr methodID, bool isStatic)
+		{
+			ID                  = methodID;
+			IsStatic            = isStatic;
+
+#if DEBUG
+			this.nameUtf8       = nameUtf8;
+			this.signatureUtf8  = signatureUtf8;
+#endif  // DEBUG
+		}
+
+		internal JniMethodInfo (string name, IntPtr signatureUtf8, IntPtr methodID, bool isStatic)
+		{
+			ID                  = methodID;
+			IsStatic            = isStatic;
+
+#if DEBUG
+			this.name           = name;
+			this.signatureUtf8  = signatureUtf8;
+#endif  // DEBUG
+		}
+
+#if DEBUG
+		static unsafe string GetUtf8String (IntPtr value)
+		{
+			if (value == IntPtr.Zero)
+				throw new NotSupportedException ();
+
+			return System.Text.Encoding.UTF8.GetString (MemoryMarshal.CreateReadOnlySpanFromNullTerminated ((byte*)value));
+		}
+#endif  // DEBUG
+
 		public override string ToString ()
 		{
 #if DEBUG
-			bool haveName   = !string.IsNullOrEmpty (name);
-			bool haveSig    = !string.IsNullOrEmpty (signature);
+			bool haveName   = !string.IsNullOrEmpty (name) || nameUtf8 != IntPtr.Zero;
+			bool haveSig    = !string.IsNullOrEmpty (signature) || signatureUtf8 != IntPtr.Zero;
 #else   // DEBUG
 			bool haveName   = false;
 			bool haveSig    = false;
@@ -73,4 +118,3 @@ public override string ToString ()
 		}
 	}
 }
-

external/Java.Interop/src/Java.Interop/Java.Interop/JniPeerMembers.JniFields.cs

@@ -202,109 +202,109 @@ partial class JniStaticFields {
 		public bool GetBooleanValue (string encodedMember)
 		{
 			var f   = GetFieldInfo (encodedMember);
-			return JniEnvironment.StaticFields.GetStaticBooleanField (Members.JniPeerType.PeerReference, f);
+			return JniEnvironment.StaticFields.GetStaticBooleanField (GetFieldDeclaringType (f).PeerReference, f);
 		}
 
 		public void SetValue (string encodedMember, bool value)
 		{
 			var f   = GetFieldInfo (encodedMember);
-			JniEnvironment.StaticFields.SetStaticBooleanField (Members.JniPeerType.PeerReference, f, value);
+			JniEnvironment.StaticFields.SetStaticBooleanField (GetFieldDeclaringType (f).PeerReference, f, value);
 		}
 
 		public sbyte GetSByteValue (string encodedMember)
 		{
 			var f   = GetFieldInfo (encodedMember);
-			return JniEnvironment.StaticFields.GetStaticByteField (Members.JniPeerType.PeerReference, f);
+			return JniEnvironment.StaticFields.GetStaticByteField (GetFieldDeclaringType (f).PeerReference, f);
 		}
 
 		public void SetValue (string encodedMember, sbyte value)
 		{
 			var f   = GetFieldInfo (encodedMember);
-			JniEnvironment.StaticFields.SetStaticByteField (Members.JniPeerType.PeerReference, f, value);
+			JniEnvironment.StaticFields.SetStaticByteField (GetFieldDeclaringType (f).PeerReference, f, value);
 		}
 
 		public char GetCharValue (string encodedMember)
 		{
 			var f   = GetFieldInfo (encodedMember);
-			return JniEnvironment.StaticFields.GetStaticCharField (Members.JniPeerType.PeerReference, f);
+			return JniEnvironment.StaticFields.GetStaticCharField (GetFieldDeclaringType (f).PeerReference, f);
 		}
 
 		public void SetValue (string encodedMember, char value)
 		{
 			var f   = GetFieldInfo (encodedMember);
-			JniEnvironment.StaticFields.SetStaticCharField (Members.JniPeerType.PeerReference, f, value);
+			JniEnvironment.StaticFields.SetStaticCharField (GetFieldDeclaringType (f).PeerReference, f, value);
 		}
 
 		public short GetInt16Value (string encodedMember)
 		{
 			var f   = GetFieldInfo (encodedMember);
-			return JniEnvironment.StaticFields.GetStaticShortField (Members.JniPeerType.PeerReference, f);
+			return JniEnvironment.StaticFields.GetStaticShortField (GetFieldDeclaringType (f).PeerReference, f);
 		}
 
 		public void SetValue (string encodedMember, short value)
 		{
 			var f   = GetFieldInfo (encodedMember);
-			JniEnvironment.StaticFields.SetStaticShortField (Members.JniPeerType.PeerReference, f, value);
+			JniEnvironment.StaticFields.SetStaticShortField (GetFieldDeclaringType (f).PeerReference, f, value);
 		}
 
 		public int GetInt32Value (string encodedMember)
 		{
 			var f   = GetFieldInfo (encodedMember);
-			return JniEnvironment.StaticFields.GetStaticIntField (Members.JniPeerType.PeerReference, f);
+			return JniEnvironment.StaticFields.GetStaticIntField (GetFieldDeclaringType (f).PeerReference, f);
 		}
 
 		public void SetValue (string encodedMember, int value)
 		{
 			var f   = GetFieldInfo (encodedMember);
-			JniEnvironment.StaticFields.SetStaticIntField (Members.JniPeerType.PeerReference, f, value);
+			JniEnvironment.StaticFields.SetStaticIntField (GetFieldDeclaringType (f).PeerReference, f, value);
 		}
 
 		public long GetInt64Value (string encodedMember)
 		{
 			var f   = GetFieldInfo (encodedMember);
-			return JniEnvironment.StaticFields.GetStaticLongField (Members.JniPeerType.PeerReference, f);
+			return JniEnvironment.StaticFields.GetStaticLongField (GetFieldDeclaringType (f).PeerReference, f);
 		}
 
 		public void SetValue (string encodedMember, long value)
 		{
 			var f   = GetFieldInfo (encodedMember);
-			JniEnvironment.StaticFields.SetStaticLongField (Members.JniPeerType.PeerReference, f, value);
+			JniEnvironment.StaticFields.SetStaticLongField (GetFieldDeclaringType (f).PeerReference, f, value);
 		}
 
 		public float GetSingleValue (string encodedMember)
 		{
 			var f   = GetFieldInfo (encodedMember);
-			return JniEnvironment.StaticFields.GetStaticFloatField (Members.JniPeerType.PeerReference, f);
+			return JniEnvironment.StaticFields.GetStaticFloatField (GetFieldDeclaringType (f).PeerReference, f);
 		}
 
 		public void SetValue (string encodedMember, float value)
 		{
 			var f   = GetFieldInfo (encodedMember);
-			JniEnvironment.StaticFields.SetStaticFloatField (Members.JniPeerType.PeerReference, f, value);
+			JniEnvironment.StaticFields.SetStaticFloatField (GetFieldDeclaringType (f).PeerReference, f, value);
 		}
 
 		public double GetDoubleValue (string encodedMember)
 		{
 			var f   = GetFieldInfo (encodedMember);
-			return JniEnvironment.StaticFields.GetStaticDoubleField (Members.JniPeerType.PeerReference, f);
+			return JniEnvironment.StaticFields.GetStaticDoubleField (GetFieldDeclaringType (f).PeerReference, f);
 		}
 
 		public void SetValue (string encodedMember, double value)
 		{
 			var f   = GetFieldInfo (encodedMember);
-			JniEnvironment.StaticFields.SetStaticDoubleField (Members.JniPeerType.PeerReference, f, value);
+			JniEnvironment.StaticFields.SetStaticDoubleField (GetFieldDeclaringType (f).PeerReference, f, value);
 		}
 
 		public JniObjectReference GetObjectValue (string encodedMember)
 		{
 			var f   = GetFieldInfo (encodedMember);
-			return JniEnvironment.StaticFields.GetStaticObjectField (Members.JniPeerType.PeerReference, f);
+			return JniEnvironment.StaticFields.GetStaticObjectField (GetFieldDeclaringType (f).PeerReference, f);
 		}
 
 		public void SetValue (string encodedMember, JniObjectReference value)
 		{
 			var f   = GetFieldInfo (encodedMember);
-			JniEnvironment.StaticFields.SetStaticObjectField (Members.JniPeerType.PeerReference, f, value);
+			JniEnvironment.StaticFields.SetStaticObjectField (GetFieldDeclaringType (f).PeerReference, f, value);
 		}
 	}}
 }

external/Java.Interop/src/Java.Interop/Java.Interop/JniPeerMembers.JniInstanceFields.cs

@@ -29,8 +29,39 @@ public JniFieldInfo GetFieldInfo (string encodedMember)
 			return InstanceFields.GetOrAdd (encodedMember, static (member, fields) => {
 				ReadOnlySpan<char> field, signature;
 				JniPeerMembers.GetNameAndSignature (member, out field, out signature);
-				return fields.Members.JniPeerType.GetInstanceField (field, signature);
+				return fields.GetFieldInfo (field, signature);
 			}, this);
 		}
+
+		JniFieldInfo GetFieldInfo (ReadOnlySpan<char> field, ReadOnlySpan<char> signature)
+		{
+			var newField = JniPeerMembers.GetReplacementFieldInfo (Members.JniPeerTypeName, field, signature);
+			if (newField.HasValue) {
+				var typeName     = newField.Value.TargetJniType ?? Members.JniPeerTypeName;
+				var fieldName    = newField.Value.TargetJniFieldName is string name ? name.AsSpan () : field;
+				var fieldSig     = newField.Value.TargetJniFieldSignature is string sig ? sig.AsSpan () : signature;
+
+				using var t = new JniType (typeName);
+				if (t.TryGetInstanceField (fieldName, fieldSig, out var f)) {
+					return f;
+				}
+			}
+			if (Members.JniPeerType.TryGetInstanceField (field, signature, out var originalField)) {
+				return originalField;
+			}
+
+			newField = JniPeerMembers.GetBaseReplacementFieldInfo (Members.ManagedPeerType, field, signature);
+			if (newField.HasValue) {
+				var typeName     = newField.Value.TargetJniType ?? Members.JniPeerTypeName;
+				var fieldName    = newField.Value.TargetJniFieldName is string name ? name.AsSpan () : field;
+				var fieldSig     = newField.Value.TargetJniFieldSignature is string sig ? sig.AsSpan () : signature;
+
+				using var t = new JniType (typeName);
+				if (t.TryGetInstanceField (fieldName, fieldSig, out var f)) {
+					return f;
+				}
+			}
+			return Members.JniPeerType.GetInstanceField (field, signature);
+		}
 	}}
 }