diff --git a/src/IKVM.MSBuild.Tasks/IkvmJsonParser.cs b/src/IKVM.MSBuild.Tasks/IkvmJsonParser.cs
index 5aba198027..238256265c 100644
--- a/src/IKVM.MSBuild.Tasks/IkvmJsonParser.cs
+++ b/src/IKVM.MSBuild.Tasks/IkvmJsonParser.cs
@@ -5,6 +5,7 @@
     using System.Collections;
     using System.Collections.Generic;
     using System.Reflection;
+    using System.Runtime.CompilerServices;
     using System.Runtime.Serialization;
     using System.Text;
 
@@ -321,7 +322,11 @@ static Dictionary<string, T> CreateMemberNameDictionary<T>(T[] members) where T
 
         static object ParseObject(Type type, string json)
         {
+#if NETFRAMEWORK
             object instance = FormatterServices.GetUninitializedObject(type);
+#else
+            object instance = RuntimeHelpers.GetUninitializedObject(type);
+#endif
 
             //The list is split into key/value pairs only, this means the split must be divisible by 2 to be valid JSON
             List<string> elems = Split(json);
diff --git a/src/IKVM.Runtime/JNI/JNIEnv.cs b/src/IKVM.Runtime/JNI/JNIEnv.cs
index 6d0963d143..265d629351 100644
--- a/src/IKVM.Runtime/JNI/JNIEnv.cs
+++ b/src/IKVM.Runtime/JNI/JNIEnv.cs
@@ -25,7 +25,9 @@ Jeroen Frijters
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Reflection;
+using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
+using System.Runtime.Serialization;
 
 using IKVM.ByteCode.Text;
 
@@ -739,7 +741,11 @@ static jobject AllocObjectImpl(JNIEnv* pEnv, RuntimeJavaType wrapper)
                     return IntPtr.Zero;
                 }
                 wrapper.Finish();
-                return pEnv->MakeLocalRef(System.Runtime.Serialization.FormatterServices.GetUninitializedObject(wrapper.TypeAsBaseType));
+#if NETFRAMEWORK
+                return pEnv->MakeLocalRef(FormatterServices.GetUninitializedObject(wrapper.TypeAsBaseType));
+#else
+                return pEnv->MakeLocalRef(RuntimeHelpers.GetUninitializedObject(wrapper.TypeAsBaseType));
+#endif
             }
             catch (RetargetableJavaException e)
             {
diff --git a/src/IKVM.Runtime/Java/Externs/sun/misc/Unsafe.cs b/src/IKVM.Runtime/Java/Externs/sun/misc/Unsafe.cs
index f62ef262f6..16202305f3 100644
--- a/src/IKVM.Runtime/Java/Externs/sun/misc/Unsafe.cs
+++ b/src/IKVM.Runtime/Java/Externs/sun/misc/Unsafe.cs
@@ -1704,7 +1704,11 @@ public static object allocateInstance(object self, global::java.lang.Class cls)
                 throw x.ToJava();
             }
 
+#if NETFRAMEWORK
             return FormatterServices.GetUninitializedObject(wrapper.TypeAsBaseType);
+#else
+            return RuntimeHelpers.GetUninitializedObject(wrapper.TypeAsBaseType);
+#endif
         }
 
         /// <summary>
diff --git a/src/IKVM.Runtime/Java/Externs/sun/reflect/ReflectionFactory.cs b/src/IKVM.Runtime/Java/Externs/sun/reflect/ReflectionFactory.cs
index b27ab6d627..9c4a43cc86 100644
--- a/src/IKVM.Runtime/Java/Externs/sun/reflect/ReflectionFactory.cs
+++ b/src/IKVM.Runtime/Java/Externs/sun/reflect/ReflectionFactory.cs
@@ -25,6 +25,8 @@ Jeroen Frijters
 using System.Reflection;
 #if !NO_REF_EMIT
 using System.Reflection.Emit;
+using System.Runtime.CompilerServices;
+
 #endif
 using System.Runtime.Serialization;
 using System.Security;
@@ -282,7 +284,11 @@ internal SerializationConstructorAccessorImpl(global::java.lang.reflect.Construc
             [SecuritySafeCritical]
             public object newInstance(object[] args)
             {
+#if NETFRAMEWORK
                 var obj = FormatterServices.GetUninitializedObject(type);
+#else
+                var obj = RuntimeHelpers.GetUninitializedObject(type);
+#endif
                 if (mw != null)
                     mw.Invoke(obj, ConvertArgs(mw.DeclaringType.GetClassLoader(), mw.GetParameters(), args));
 
@@ -966,13 +972,17 @@ public object newInstance(object[] args)
 
         }
 
-        private sealed class FastSerializationConstructorAccessorImpl : global::sun.reflect.ConstructorAccessor
+        sealed class FastSerializationConstructorAccessorImpl : global::sun.reflect.ConstructorAccessor
         {
 
-            private static readonly MethodInfo GetTypeFromHandleMethod = typeof(Type).GetMethod("GetTypeFromHandle", new Type[] { typeof(RuntimeTypeHandle) });
-            private static readonly MethodInfo GetUninitializedObjectMethod = typeof(FormatterServices).GetMethod("GetUninitializedObject", new Type[] { typeof(Type) });
-            private delegate object InvokeCtor();
-            private InvokeCtor invoker;
+            static readonly MethodInfo GetTypeFromHandleMethod = typeof(Type).GetMethod(nameof(Type.GetTypeFromHandle), new[] { typeof(RuntimeTypeHandle) });
+#if NETFRAMEWORK
+            static readonly MethodInfo GetUninitializedObjectMethod = typeof(FormatterServices).GetMethod(nameof(FormatterServices.GetUninitializedObject), new[] { typeof(Type) });
+#else
+            static readonly MethodInfo GetUninitializedObjectMethod = typeof(RuntimeHelpers).GetMethod(nameof(RuntimeHelpers.GetUninitializedObject), new[] { typeof(Type) });
+#endif
+            delegate object InvokeCtor();
+            InvokeCtor invoker;
 
             internal FastSerializationConstructorAccessorImpl(global::java.lang.reflect.Constructor constructorToCall, global::java.lang.Class classToInstantiate)
             {
diff --git a/src/IKVM.Runtime/RuntimeAssemblyClassLoader.cs b/src/IKVM.Runtime/RuntimeAssemblyClassLoader.cs
index c276613ef0..0fc236e1d0 100644
--- a/src/IKVM.Runtime/RuntimeAssemblyClassLoader.cs
+++ b/src/IKVM.Runtime/RuntimeAssemblyClassLoader.cs
@@ -31,6 +31,9 @@ Jeroen Frijters
 using IKVM.Attributes;
 using IKVM.Runtime.Syntax;
 
+using System.Runtime.CompilerServices;
+
+
 #if IMPORTER || EXPORTER
 using IKVM.Reflection;
 
@@ -1253,7 +1256,11 @@ void InitializeJavaClassLoader(JavaClassLoaderConstructionInProgress jclcip, Typ
         [System.Security.SecuritySafeCritical]
         static object GetUninitializedObject(Type type)
         {
+#if NETFRAMEWORK
             return FormatterServices.GetUninitializedObject(type);
+#else
+            return RuntimeHelpers.GetUninitializedObject(type);
+#endif
         }
 
         static void LoadCustomClassLoaderRedirects(RuntimeContext context)
diff --git a/src/IKVM.Tools.Exporter/IkvmExporterContext.NetCore.cs b/src/IKVM.Tools.Exporter/IkvmExporterContext.NetCore.cs
index f263decfd8..2188bf4fd4 100644
--- a/src/IKVM.Tools.Exporter/IkvmExporterContext.NetCore.cs
+++ b/src/IKVM.Tools.Exporter/IkvmExporterContext.NetCore.cs
@@ -1,17 +1,12 @@
 #if NETCOREAPP
 
 using System;
-using System.IO;
 using System.Reflection;
 using System.Runtime.Loader;
-using System.Runtime.Serialization.Formatters.Binary;
+using System.Text.Json;
 using System.Threading;
 using System.Threading.Tasks;
 
-using Microsoft.Extensions.DependencyModel.Resolution;
-
-using System.Text.Json;
-
 namespace IKVM.Tools.Exporter
 {