Make okhttp3 ,feign http9.x plugin to support Java 14 (#5745)

CHANGES.md

@@ -7,6 +7,8 @@ Release Notes.
 #### Project
 
 #### Java Agent
+Make the Feign plugin to support Java 14
+Make the okhttp3 plugin to support Java 14
 
 #### OAP-Backend
 * Add the `@SuperDataset` annotation for BrowserErrorLog.

apm-sniffer/apm-sdk-plugin/feign-default-http-9.x-plugin/src/main/java/org/apache/skywalking/apm/plugin/feign/http/v9/DefaultHttpClientInterceptor.java

@@ -22,7 +22,6 @@ import feign.Request;
 import feign.Response;
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
-import java.lang.reflect.Modifier;
 import java.net.URL;
 import java.util.ArrayList;
 import java.util.Collection;
@@ -103,10 +102,6 @@ public class DefaultHttpClientInterceptor implements InstanceMethodsAroundInterc
         }
 
         Field headersField = Request.class.getDeclaredField("headers");
-        Field modifiersField = Field.class.getDeclaredField("modifiers");
-        modifiersField.setAccessible(true);
-        modifiersField.setInt(headersField, headersField.getModifiers() & ~Modifier.FINAL);
-
         headersField.setAccessible(true);
         Map<String, Collection<String>> headers = new LinkedHashMap<String, Collection<String>>();
         CarrierItem next = contextCarrier.items();

apm-sniffer/apm-sdk-plugin/okhttp-3.x-plugin/src/main/java/org/apache/skywalking/apm/plugin/okhttp/v3/AsyncCallInterceptor.java

@@ -20,7 +20,6 @@ package org.apache.skywalking.apm.plugin.okhttp.v3;
 
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
-import java.lang.reflect.Modifier;
 import okhttp3.Headers;
 import okhttp3.HttpUrl;
 import okhttp3.Request;
@@ -74,10 +73,6 @@ public class AsyncCallInterceptor implements InstanceConstructorInterceptor, Ins
         SpanLayer.asHttp(span);
 
         Field headersField = Request.class.getDeclaredField("headers");
-        Field modifiersField = Field.class.getDeclaredField("modifiers");
-        modifiersField.setAccessible(true);
-        modifiersField.setInt(headersField, headersField.getModifiers() & ~Modifier.FINAL);
-
         headersField.setAccessible(true);
         Headers.Builder headerBuilder = request.headers().newBuilder();
         CarrierItem next = contextCarrier.items();

apm-sniffer/apm-sdk-plugin/okhttp-3.x-plugin/src/main/java/org/apache/skywalking/apm/plugin/okhttp/v3/RealCallInterceptor.java

@@ -20,7 +20,6 @@ package org.apache.skywalking.apm.plugin.okhttp.v3;
 
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
-import java.lang.reflect.Modifier;
 import okhttp3.Headers;
 import okhttp3.HttpUrl;
 import okhttp3.Request;
@@ -70,10 +69,6 @@ public class RealCallInterceptor implements InstanceMethodsAroundInterceptor, In
         SpanLayer.asHttp(span);
 
         Field headersField = Request.class.getDeclaredField("headers");
-        Field modifiersField = Field.class.getDeclaredField("modifiers");
-        modifiersField.setAccessible(true);
-        modifiersField.setInt(headersField, headersField.getModifiers() & ~Modifier.FINAL);
-
         headersField.setAccessible(true);
         Headers.Builder headerBuilder = request.headers().newBuilder();
         CarrierItem next = contextCarrier.items();