diff --git a/external/Java.Interop b/external/Java.Interop
index c825dcad8e7..56b7eeb771a 160000
--- a/external/Java.Interop
+++ b/external/Java.Interop
@@ -1 +1 @@
-Subproject commit c825dcad8e7fe2e1ba5846a592a02f6a578db991
+Subproject commit 56b7eeb771aceb7d47b31a4337f7b0e73ba74447
diff --git a/src-ThirdParty/System.Diagnostics.CodeAnalysis/NullableAttributes.cs b/src-ThirdParty/System.Diagnostics.CodeAnalysis/NullableAttributes.cs
new file mode 100644
index 00000000000..ba4e92f0106
--- /dev/null
+++ b/src-ThirdParty/System.Diagnostics.CodeAnalysis/NullableAttributes.cs
@@ -0,0 +1,133 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace System.Diagnostics.CodeAnalysis
+{
+	/// <summary>Specifies that null is allowed as an input even if the corresponding type disallows it.</summary>
+	[AttributeUsage (AttributeTargets.Field | AttributeTargets.Parameter | AttributeTargets.Property, Inherited = false)]
+#if INTERNAL_NULLABLE_ATTRIBUTES
+    internal
+#else
+	public
+#endif
+	sealed class AllowNullAttribute : Attribute
+	{ }
+
+	/// <summary>Specifies that null is disallowed as an input even if the corresponding type allows it.</summary>
+	[AttributeUsage (AttributeTargets.Field | AttributeTargets.Parameter | AttributeTargets.Property, Inherited = false)]
+#if INTERNAL_NULLABLE_ATTRIBUTES
+    internal
+#else
+	public
+#endif
+	sealed class DisallowNullAttribute : Attribute
+	{ }
+
+	/// <summary>Specifies that an output may be null even if the corresponding type disallows it.</summary>
+	[AttributeUsage (AttributeTargets.Field | AttributeTargets.Parameter | AttributeTargets.Property | AttributeTargets.ReturnValue, Inherited = false)]
+#if INTERNAL_NULLABLE_ATTRIBUTES
+    internal
+#else
+	public
+#endif
+	sealed class MaybeNullAttribute : Attribute
+	{ }
+
+	/// <summary>Specifies that an output will not be null even if the corresponding type allows it.</summary>
+	[AttributeUsage (AttributeTargets.Field | AttributeTargets.Parameter | AttributeTargets.Property | AttributeTargets.ReturnValue, Inherited = false)]
+#if INTERNAL_NULLABLE_ATTRIBUTES
+    internal
+#else
+	public
+#endif
+	sealed class NotNullAttribute : Attribute
+	{ }
+
+	/// <summary>Specifies that when a method returns <see cref="ReturnValue"/>, the parameter may be null even if the corresponding type disallows it.</summary>
+	[AttributeUsage (AttributeTargets.Parameter, Inherited = false)]
+#if INTERNAL_NULLABLE_ATTRIBUTES
+    internal
+#else
+	public
+#endif
+	sealed class MaybeNullWhenAttribute : Attribute
+	{
+		/// <summary>Initializes the attribute with the specified return value condition.</summary>
+		/// <param name="returnValue">
+		/// The return value condition. If the method returns this value, the associated parameter may be null.
+		/// </param>
+		public MaybeNullWhenAttribute (bool returnValue) => ReturnValue = returnValue;
+
+		/// <summary>Gets the return value condition.</summary>
+		public bool ReturnValue { get; }
+	}
+
+	/// <summary>Specifies that when a method returns <see cref="ReturnValue"/>, the parameter will not be null even if the corresponding type allows it.</summary>
+	[AttributeUsage (AttributeTargets.Parameter, Inherited = false)]
+#if INTERNAL_NULLABLE_ATTRIBUTES
+    internal
+#else
+	public
+#endif
+	sealed class NotNullWhenAttribute : Attribute
+	{
+		/// <summary>Initializes the attribute with the specified return value condition.</summary>
+		/// <param name="returnValue">
+		/// The return value condition. If the method returns this value, the associated parameter will not be null.
+		/// </param>
+		public NotNullWhenAttribute (bool returnValue) => ReturnValue = returnValue;
+
+		/// <summary>Gets the return value condition.</summary>
+		public bool ReturnValue { get; }
+	}
+
+	/// <summary>Specifies that the output will be non-null if the named parameter is non-null.</summary>
+	[AttributeUsage (AttributeTargets.Parameter | AttributeTargets.Property | AttributeTargets.ReturnValue, AllowMultiple = true, Inherited = false)]
+#if INTERNAL_NULLABLE_ATTRIBUTES
+    internal
+#else
+	public
+#endif
+	sealed class NotNullIfNotNullAttribute : Attribute
+	{
+		/// <summary>Initializes the attribute with the associated parameter name.</summary>
+		/// <param name="parameterName">
+		/// The associated parameter name.  The output will be non-null if the argument to the parameter specified is non-null.
+		/// </param>
+		public NotNullIfNotNullAttribute (string parameterName) => ParameterName = parameterName;
+
+		/// <summary>Gets the associated parameter name.</summary>
+		public string ParameterName { get; }
+	}
+
+	/// <summary>Applied to a method that will never return under any circumstance.</summary>
+	[AttributeUsage (AttributeTargets.Method, Inherited = false)]
+#if INTERNAL_NULLABLE_ATTRIBUTES
+    internal
+#else
+	public
+#endif
+	sealed class DoesNotReturnAttribute : Attribute
+	{ }
+
+	/// <summary>Specifies that the method will not return if the associated Boolean parameter is passed the specified value.</summary>
+	[AttributeUsage (AttributeTargets.Parameter, Inherited = false)]
+#if INTERNAL_NULLABLE_ATTRIBUTES
+    internal
+#else
+	public
+#endif
+	sealed class DoesNotReturnIfAttribute : Attribute
+	{
+		/// <summary>Initializes the attribute with the specified parameter value.</summary>
+		/// <param name="parameterValue">
+		/// The condition parameter value. Code after the method will be considered unreachable by diagnostics if the argument to
+		/// the associated parameter matches this value.
+		/// </param>
+		public DoesNotReturnIfAttribute (bool parameterValue) => ParameterValue = parameterValue;
+
+		/// <summary>Gets the condition parameter value.</summary>
+		public bool ParameterValue { get; }
+	}
+}
diff --git a/src/Xamarin.Android.Build.Tasks/Xamarin.Android.Build.Tasks.csproj b/src/Xamarin.Android.Build.Tasks/Xamarin.Android.Build.Tasks.csproj
index d2304de5a5d..b13c9534cc1 100644
--- a/src/Xamarin.Android.Build.Tasks/Xamarin.Android.Build.Tasks.csproj
+++ b/src/Xamarin.Android.Build.Tasks/Xamarin.Android.Build.Tasks.csproj
@@ -14,7 +14,7 @@
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <OutputPath>$(MicrosoftAndroidSdkOutDir)</OutputPath>
     <AppendTargetFrameworkToOutputPath>false</AppendTargetFrameworkToOutputPath>
-    <DefineConstants>$(DefineConstants);TRACE;HAVE_CECIL;MSBUILD;ANDROID_24;ANDROID_26;ANDROID_31</DefineConstants>
+    <DefineConstants>$(DefineConstants);TRACE;HAVE_CECIL;MSBUILD;INTERNAL_NULLABLE_ATTRIBUTES;ANDROID_24;ANDROID_26;ANDROID_31</DefineConstants>
     <AndroidGeneratedClassDirectory Condition=" '$(AndroidGeneratedClassDirectory)' == '' ">..\..\src\Mono.Android\obj\$(Configuration)\$(DotNetTargetFramework)\android-$(AndroidLatestStablePlatformId)\mcw</AndroidGeneratedClassDirectory>
     <NoWarn>8632</NoWarn>
     <SignAssembly>false</SignAssembly>
@@ -165,6 +165,9 @@
     <Compile Include="..\..\src-ThirdParty\StrongNameSigner\SigningHelper.cs">
       <Link>Utilities\%(Filename)%(Extension)</Link>
     </Compile>
+    <Compile Include="..\..\src-ThirdParty\System.Diagnostics.CodeAnalysis\NullableAttributes.cs">
+      <Link>Utilities\%(Filename)%(Extension)</Link>
+    </Compile>
   </ItemGroup>
 
   <ItemGroup>