diff --git a/src/Neo.Compiler.CSharp/CompilationContext.cs b/src/Neo.Compiler.CSharp/CompilationContext.cs
index 17d9ebcb2..0d166c8bf 100644
--- a/src/Neo.Compiler.CSharp/CompilationContext.cs
+++ b/src/Neo.Compiler.CSharp/CompilationContext.cs
@@ -325,9 +325,6 @@ private void ProcessClass(SemanticModel model, INamedTypeSymbol symbol)
                 {
                     return;
                 }
-                // Process the target contract
-                // add this compilation context
-                _engine.Contexts.Add(symbol, this);
 
                 foreach (var attribute in symbol.GetAttributesWithInherited())
                 {
diff --git a/src/Neo.Compiler.CSharp/CompilationEngine.cs b/src/Neo.Compiler.CSharp/CompilationEngine.cs
index e9719d960..fa9e42227 100644
--- a/src/Neo.Compiler.CSharp/CompilationEngine.cs
+++ b/src/Neo.Compiler.CSharp/CompilationEngine.cs
@@ -118,14 +118,14 @@ private List<CompilationContext> CompileProjectContracts(Compilation compilation
                 foreach (var classNode in classNodes)
                 {
                     var classSymbol = semanticModel.GetDeclaredSymbol(classNode);
-                    if (classSymbol != null && IsDerivedFromSmartContract(classSymbol, "Neo.SmartContract.Framework.SmartContract", semanticModel))
+                    if (classSymbol is { IsAbstract: false, DeclaredAccessibility: Accessibility.Public } && IsDerivedFromSmartContract(classSymbol, "Neo.SmartContract.Framework.SmartContract", semanticModel))
                     {
                         allSmartContracts.Add(classSymbol);
                         classDependencies[classSymbol] = new List<INamedTypeSymbol>();
                         foreach (var member in classSymbol.GetMembers())
                         {
                             var memberTypeSymbol = (member as IFieldSymbol)?.Type ?? (member as IPropertySymbol)?.Type;
-                            if (memberTypeSymbol is INamedTypeSymbol namedTypeSymbol && allSmartContracts.Contains(namedTypeSymbol))
+                            if (memberTypeSymbol is INamedTypeSymbol namedTypeSymbol && allSmartContracts.Contains(namedTypeSymbol) && !namedTypeSymbol.IsAbstract)
                             {
                                 classDependencies[classSymbol].Add(namedTypeSymbol);
                             }
@@ -138,7 +138,15 @@ private List<CompilationContext> CompileProjectContracts(Compilation compilation
             if (classDependencies.Count == 0) throw new FormatException("No valid neo SmartContract found. Please make sure your contract is subclass of SmartContract and is not abstract.");
             // Check contract dependencies, make sure there is no cycle in the dependency graph
             var sortedClasses = TopologicalSort(classDependencies);
-            sortedClasses.ForEach(c => new CompilationContext(this, c).Compile());
+
+            sortedClasses.ForEach(c =>
+                {
+                    var context = new CompilationContext(this, c);
+                    context.Compile();
+                    // Process the target contract add this compilation context
+                    this.Contexts.Add(c, context);
+                });
+
             return Contexts.Select(p => p.Value).ToList();
         }
 
diff --git a/src/Neo.SmartContract.Framework/Interfaces/IOracle.cs b/src/Neo.SmartContract.Framework/Interfaces/IOracle.cs
new file mode 100644
index 000000000..3b6814769
--- /dev/null
+++ b/src/Neo.SmartContract.Framework/Interfaces/IOracle.cs
@@ -0,0 +1,30 @@
+using Neo.SmartContract.Framework.Native;
+
+namespace Neo.SmartContract.Framework.Interfaces;
+
+/// <summary>
+/// Interface of oracle callback method
+/// </summary>
+public interface IOracle
+{
+    /// <summary>
+    /// This method is called after the Oracle receives response from requested URL
+    /// </summary>
+    /// <param name="requestedUrl">The url of the data source</param>
+    /// <param name="userData">Extra oracle request data specified by user</param>
+    /// <param name="oracleResponse">Oracle response code <see cref="OracleResponseCode"/> from data source</param>
+    /// <param name="jsonString">The oracle response data in format of json string</param>
+    ///
+    /// <example>
+    /// public static void OnOracleResponse(string url, object userData, OracleResponseCode code, string result)
+    /// {
+    ///     if (Runtime.CallingScriptHash != Oracle.Hash) throw new Exception("Unauthorized!");
+    ///     Storage.Put(Storage.CurrentContext, PreData, result);
+    /// }
+    /// </example>
+    public void OnOracleResponse(
+        string requestedUrl,
+        object userData,
+        OracleResponseCode oracleResponse,
+        string jsonString);
+}
diff --git a/tests/Neo.SmartContract.Framework.TestContracts/Contract_IOracle.cs b/tests/Neo.SmartContract.Framework.TestContracts/Contract_IOracle.cs
new file mode 100644
index 000000000..a85791d0d
--- /dev/null
+++ b/tests/Neo.SmartContract.Framework.TestContracts/Contract_IOracle.cs
@@ -0,0 +1,18 @@
+using Neo.SmartContract.Framework.Interfaces;
+using Neo.SmartContract.Framework.Native;
+using Neo.SmartContract.Framework.Services;
+
+namespace Neo.SmartContract.Framework.UnitTests.TestClasses
+{
+    public class Contract_IOracle : SmartContract, IOracle
+    {
+        private const string PreData = "PreData";
+
+        public void OnOracleResponse(string url, object userData, OracleResponseCode code, string result)
+        {
+            if (Runtime.CallingScriptHash != Oracle.Hash)
+                throw new System.Exception("Unauthorized!");
+            Storage.Put(Storage.CurrentContext, PreData, result);
+        }
+    }
+}
diff --git a/tests/Neo.SmartContract.Framework.UnitTests/Services/OracleTest.cs b/tests/Neo.SmartContract.Framework.UnitTests/Services/OracleTest.cs
new file mode 100644
index 000000000..9935d2b51
--- /dev/null
+++ b/tests/Neo.SmartContract.Framework.UnitTests/Services/OracleTest.cs
@@ -0,0 +1,30 @@
+using System.Security.Cryptography;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Neo.Network.P2P.Payloads;
+using Neo.SmartContract.TestEngine;
+using Neo.VM;
+using Neo.Wallets;
+
+namespace Neo.SmartContract.Framework.UnitTests.Services
+{
+    [TestClass]
+    public class OracleTest
+    {
+        private TestEngine.TestEngine _engine;
+
+        [TestInitialize]
+        public void Init()
+        {
+            _engine = new TestEngine.TestEngine();
+            _engine.AddEntryScript(Utils.Extensions.TestContractRoot + "Contract_IOracle.cs");
+        }
+
+        [TestMethod]
+        public void Test_OracleResponse()
+        {
+            _engine.Reset();
+            var result = _engine.ExecuteTestCaseStandard("onOracleResponse", "http://127.0.0.1", "test", 0x14, "{}");
+            Assert.AreEqual(VMState.FAULT, _engine.State);
+        }
+    }
+}