diff --git a/bus/EasyCaching.Bus.Zookeeper/DefaultZookeeperBus.cs b/bus/EasyCaching.Bus.Zookeeper/DefaultZookeeperBus.cs
index e314bf79..c7cb7999 100644
--- a/bus/EasyCaching.Bus.Zookeeper/DefaultZookeeperBus.cs
+++ b/bus/EasyCaching.Bus.Zookeeper/DefaultZookeeperBus.cs
@@ -41,7 +41,7 @@ public class DefaultZookeeperBus : EasyCachingAbstractBus
         /// <summary>
         /// lock
         /// </summary>
-        private readonly object _zkEventLock = new object();
+        private readonly Lock _zkEventLock = new Lock();
 
         /// <summary>
         /// The serializer.
@@ -214,7 +214,7 @@ private async Task SubscribeDataChange(WatchedEvent @event)
         /// <returns></returns>
         private async Task ReZkConnect()
         {
-            if (!Monitor.TryEnter(_zkEventLock, _zkBusOptions.ConnectionTimeout))
+            if (!_zkEventLock.TryEnter(_zkBusOptions.ConnectionTimeout))
                 return;
             try
             {
@@ -234,7 +234,7 @@ private async Task ReZkConnect()
             }
             finally
             {
-                Monitor.Exit(_zkEventLock);
+                _zkEventLock.Exit();
             }
         }
 
diff --git a/bus/EasyCaching.Bus.Zookeeper/EasyCaching.Bus.Zookeeper.csproj b/bus/EasyCaching.Bus.Zookeeper/EasyCaching.Bus.Zookeeper.csproj
index 5d754db8..8459c1e8 100644
--- a/bus/EasyCaching.Bus.Zookeeper/EasyCaching.Bus.Zookeeper.csproj
+++ b/bus/EasyCaching.Bus.Zookeeper/EasyCaching.Bus.Zookeeper.csproj
@@ -3,7 +3,7 @@
 	<Import Project="../../build/version.props" />
 	<Import Project="../../build/releasenotes.props" />
 	<PropertyGroup>
-		<TargetFrameworks>netstandard2.0;net6.0</TargetFrameworks>
+		<TargetFrameworks>netstandard2.0;net6.0;net9.0</TargetFrameworks>
 		<Owners>ncc;Catcher Wong</Owners>
 		<Authors>ncc;Catcher Wong</Authors>
 		<VersionPrefix>$(EasyCachingZookeeperBusPackageVersion)</VersionPrefix>
diff --git a/src/EasyCaching.Core/DistributedLock/DistributedLock.cs b/src/EasyCaching.Core/DistributedLock/DistributedLock.cs
index 4ae267c0..ec93bd05 100644
--- a/src/EasyCaching.Core/DistributedLock/DistributedLock.cs
+++ b/src/EasyCaching.Core/DistributedLock/DistributedLock.cs
@@ -9,7 +9,7 @@ namespace EasyCaching.Core.DistributedLock
     public class DistributedLock : MemoryLock
     {
         private readonly IDistributedLockProvider _provider;
-        private readonly object _syncObj = new object();
+        private readonly Lock _syncObj = new Lock();
         private readonly DistributedLockOptions _options;
         private readonly ILogger _logger;
 
diff --git a/src/EasyCaching.Core/DistributedLock/MemoryLock.cs b/src/EasyCaching.Core/DistributedLock/MemoryLock.cs
index c1d01f57..ac263e2a 100644
--- a/src/EasyCaching.Core/DistributedLock/MemoryLock.cs
+++ b/src/EasyCaching.Core/DistributedLock/MemoryLock.cs
@@ -16,7 +16,7 @@ public class MemoryLock : IDistributedLock
 
         public string Key { get; }
 
-        private readonly object _syncObj = new object();
+        private readonly Lock _syncObj = new Lock();
 
         public MemoryLock(string key) => Key = key;
 
diff --git a/src/EasyCaching.Core/DistributedLock/RefCounter.cs b/src/EasyCaching.Core/DistributedLock/RefCounter.cs
deleted file mode 100644
index d5f8c189..00000000
--- a/src/EasyCaching.Core/DistributedLock/RefCounter.cs
+++ /dev/null
@@ -1,59 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Runtime.CompilerServices;
-using System.Threading;
-
-namespace EasyCaching.Core.DistributedLock
-{
-    internal class RefCounter<T>
-    {
-        private int _refCount = 1;
-
-        public RefCounter(T value) => Value = value;
-
-        public T Value { get; }
-
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public int Increment() => Interlocked.Increment(ref _refCount);
-
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public int Decrement() => Interlocked.Decrement(ref _refCount);
-    }
-
-    internal class RefCounterPool<TKey, TValue> where TValue : class
-    {
-        private readonly IDictionary<TKey, RefCounter<TValue>> _dictionary;
-
-        public RefCounterPool() => _dictionary = new Dictionary<TKey, RefCounter<TValue>>();
-
-        public TValue GetOrAdd(TKey key, Func<TKey, TValue> valueFactory)
-        {
-            if (valueFactory == null) throw new ArgumentNullException(nameof(valueFactory));
-
-            RefCounter<TValue> item;
-            lock (_dictionary)
-            {
-                if (!_dictionary.TryGetValue(key, out item))
-                    return (_dictionary[key] = new RefCounter<TValue>(valueFactory(key))).Value;
-            }
-
-            item.Increment();
-
-            return item.Value;
-        }
-
-        public TValue TryRemove(TKey key)
-        {
-            RefCounter<TValue> item;
-
-            lock (_dictionary)
-            {
-                if (!_dictionary.TryGetValue(key, out item) || item.Decrement() > 0) return null;
-
-                _dictionary.Remove(key);
-            }
-
-            return item.Value;
-        }
-    }
-}
diff --git a/src/EasyCaching.Core/EasyCaching.Core.csproj b/src/EasyCaching.Core/EasyCaching.Core.csproj
index 34d1a4d7..378653a2 100644
--- a/src/EasyCaching.Core/EasyCaching.Core.csproj
+++ b/src/EasyCaching.Core/EasyCaching.Core.csproj
@@ -2,7 +2,8 @@
 	<Import Project="../../build/version.props" />
 	<Import Project="../../build/releasenotes.props" />
 	<PropertyGroup>
-		<TargetFrameworks>netstandard2.0;net6.0</TargetFrameworks>
+		<TargetFrameworks>netstandard2.0;net6.0;net9.0</TargetFrameworks>
+		<LangVersion>Preview</LangVersion>
 		<Owners>ncc;Catcher Wong</Owners>
 		<Authors>ncc;Catcher Wong</Authors>
 		<VersionPrefix>$(EasyCachingCorePackageVersion)</VersionPrefix>
@@ -36,12 +37,20 @@
 		<PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="3.1.0" />
 		<PackageReference Include="Microsoft.Extensions.Logging" Version="3.1.0" />
 		<PackageReference Include="System.Diagnostics.DiagnosticSource" Version="4.7.0" />
+		<PackageReference Include="Backport.System.Threading.Lock" Version="1.0.1" />
 	</ItemGroup>
 
 	<ItemGroup Condition="'$(TargetFramework)' == 'net6.0'">
 		<PackageReference Include="Microsoft.Extensions.Options.ConfigurationExtensions" Version="6.0.0" />
 		<PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="6.0.0" />
 		<PackageReference Include="Microsoft.Extensions.Logging" Version="6.0.0" />
+		<PackageReference Include="Backport.System.Threading.Lock" Version="1.0.1" />
+	</ItemGroup>
+
+	<ItemGroup Condition="'$(TargetFramework)' == 'net9.0'">
+		<PackageReference Include="Microsoft.Extensions.Options.ConfigurationExtensions" Version="8.0.0" />
+		<PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="8.0.0" />
+		<PackageReference Include="Microsoft.Extensions.Logging" Version="8.0.0" />
 	</ItemGroup>
 
 	<ItemGroup>