diff --git a/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/conf/Constants.java b/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/conf/Constants.java
index df715e965..0fd98f0c1 100644
--- a/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/conf/Constants.java
+++ b/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/conf/Constants.java
@@ -30,4 +30,6 @@ public class Constants {
     // The name of the layer that represents agent-installed services,
     // which is defined at https://github.com/apache/skywalking/blob/85ce1645be53e46286f36c0ea206c60db2d1a716/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/analysis/Layer.java#L30
     public static String EVENT_LAYER_NAME = "GENERAL";
+
+    public static int NULL_VALUE = 0;
 }
diff --git a/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/context/trace/AbstractTracingSpan.java b/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/context/trace/AbstractTracingSpan.java
index 0fad5e82c..83736bd5d 100644
--- a/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/context/trace/AbstractTracingSpan.java
+++ b/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/context/trace/AbstractTracingSpan.java
@@ -24,6 +24,7 @@ import java.util.List;
 import java.util.Map;
 import org.apache.skywalking.apm.agent.core.boot.ServiceManager;
 import org.apache.skywalking.apm.agent.core.conf.Config;
+import org.apache.skywalking.apm.agent.core.conf.Constants;
 import org.apache.skywalking.apm.agent.core.context.ContextManager;
 import org.apache.skywalking.apm.agent.core.context.TracingContext;
 import org.apache.skywalking.apm.agent.core.context.status.StatusCheckService;
@@ -32,7 +33,6 @@ import org.apache.skywalking.apm.agent.core.context.tag.Tags;
 import org.apache.skywalking.apm.agent.core.context.util.KeyValuePair;
 import org.apache.skywalking.apm.agent.core.context.util.TagValuePair;
 import org.apache.skywalking.apm.agent.core.context.util.ThrowableTransformer;
-import org.apache.skywalking.apm.agent.core.dictionary.DictionaryUtil;
 import org.apache.skywalking.apm.network.language.agent.v3.SpanObject;
 import org.apache.skywalking.apm.network.language.agent.v3.SpanType;
 import org.apache.skywalking.apm.network.trace.component.Component;
@@ -274,7 +274,7 @@ public abstract class AbstractTracingSpan implements AbstractSpan {
         if (this.layer != null) {
             spanBuilder.setSpanLayerValue(this.layer.getCode());
         }
-        if (componentId != DictionaryUtil.nullValue()) {
+        if (componentId != Constants.NULL_VALUE) {
             spanBuilder.setComponentId(componentId);
         }
         spanBuilder.setIsError(errorOccurred);
diff --git a/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/context/trace/EntrySpan.java b/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/context/trace/EntrySpan.java
index 860e7d349..f89adaa93 100644
--- a/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/context/trace/EntrySpan.java
+++ b/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/context/trace/EntrySpan.java
@@ -18,8 +18,8 @@
 
 package org.apache.skywalking.apm.agent.core.context.trace;
 
+import org.apache.skywalking.apm.agent.core.conf.Constants;
 import org.apache.skywalking.apm.agent.core.context.TracingContext;
-import org.apache.skywalking.apm.agent.core.dictionary.DictionaryUtil;
 import org.apache.skywalking.apm.network.trace.component.Component;
 
 /**
@@ -105,7 +105,7 @@ public class EntrySpan extends StackBasedTracingSpan {
     }
 
     private void clearWhenRestart() {
-        this.componentId = DictionaryUtil.nullValue();
+        this.componentId = Constants.NULL_VALUE;
         this.layer = null;
         this.logs = null;
         this.tags = null;
diff --git a/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/dictionary/DictionaryUtil.java b/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/dictionary/DictionaryUtil.java
deleted file mode 100644
index d02356528..000000000
--- a/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/dictionary/DictionaryUtil.java
+++ /dev/null
@@ -1,29 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-package org.apache.skywalking.apm.agent.core.dictionary;
-
-public class DictionaryUtil {
-    public static int nullValue() {
-        return 0;
-    }
-
-    public static boolean isNull(int id) {
-        return id == nullValue();
-    }
-}
diff --git a/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/dictionary/Found.java b/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/dictionary/Found.java
deleted file mode 100644
index 0d1328fec..000000000
--- a/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/dictionary/Found.java
+++ /dev/null
@@ -1,25 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-package org.apache.skywalking.apm.agent.core.dictionary;
-
-public class Found extends PossibleFound {
-    public Found(int value) {
-        super(value);
-    }
-}
diff --git a/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/dictionary/NotFound.java b/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/dictionary/NotFound.java
deleted file mode 100644
index cb5e88cb1..000000000
--- a/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/dictionary/NotFound.java
+++ /dev/null
@@ -1,25 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-package org.apache.skywalking.apm.agent.core.dictionary;
-
-public class NotFound extends PossibleFound {
-    public NotFound() {
-        super();
-    }
-}
diff --git a/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/dictionary/PossibleFound.java b/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/dictionary/PossibleFound.java
deleted file mode 100644
index ae37029f6..000000000
--- a/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/dictionary/PossibleFound.java
+++ /dev/null
@@ -1,68 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-package org.apache.skywalking.apm.agent.core.dictionary;
-
-/**
- * The <code>PossibleFound</code> represents a value, which may needEnhance or not.
- */
-public abstract class PossibleFound {
-    private boolean found;
-    private int value;
-
-    PossibleFound(int value) {
-        this.found = true;
-        this.value = value;
-    }
-
-    PossibleFound() {
-        this.found = false;
-    }
-
-    public void doInCondition(Found condition1, NotFound condition2) {
-        if (found) {
-            condition1.doProcess(value);
-        } else {
-            condition2.doProcess();
-        }
-    }
-
-    public Object doInCondition(FoundAndObtain condition1, NotFoundAndObtain condition2) {
-        if (found) {
-            return condition1.doProcess(value);
-        } else {
-            return condition2.doProcess();
-        }
-    }
-
-    public interface Found {
-        void doProcess(int value);
-    }
-
-    public interface NotFound {
-        void doProcess();
-    }
-
-    public interface FoundAndObtain {
-        Object doProcess(int value);
-    }
-
-    public interface NotFoundAndObtain {
-        Object doProcess();
-    }
-}
diff --git a/apm-sniffer/apm-agent-core/src/test/java/org/apache/skywalking/apm/agent/core/dictionary/DictionaryUtilTests.java b/apm-sniffer/apm-agent-core/src/test/java/org/apache/skywalking/apm/agent/core/dictionary/DictionaryUtilTests.java
deleted file mode 100644
index bacdf67fa..000000000
--- a/apm-sniffer/apm-agent-core/src/test/java/org/apache/skywalking/apm/agent/core/dictionary/DictionaryUtilTests.java
+++ /dev/null
@@ -1,36 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-package org.apache.skywalking.apm.agent.core.dictionary;
-
-import org.junit.Assert;
-import org.junit.Test;
-
-public class DictionaryUtilTests {
-
-    @Test
-    public void testNullValue() {
-        Assert.assertEquals(0, DictionaryUtil.nullValue());
-    }
-
-    @Test
-    public void testIsNull() {
-        Assert.assertEquals(false, DictionaryUtil.isNull(1));
-        Assert.assertEquals(true, DictionaryUtil.isNull(0));
-    }
-}