[apache#1567] fix(spark): Let Spark use its own NettyUtils

client-spark/spark2-shaded/pom.xml

@@ -213,6 +213,8 @@
                           to="lib${rss.shade.native.packageName}_netty_transport_native_kqueue_aarch_64.jnilib"
                           type="glob"></mapper>
                 </move>
+                <!-- Delete NettyUtils, let Spark use its own NettyUtils -->
+                <delete dir="${project.build.directory}/unpacked/org/apache/spark/network"/>
                 <echo message="repackaging netty jar"></echo>
                 <jar destfile="${project.build.directory}/${project.artifactId}-${project.version}.jar"
                      basedir="${project.build.directory}/unpacked"/>

client-spark/spark2/src/main/java/org/apache/spark/network/util/NettyUtils.java

@@ -39,6 +39,11 @@
 /**
  * copy from spark, In order to override the createPooledByteBufAllocator method, the property
  * DEFAULT_TINY_CACHE_SIZE does not exist in netty>4.1.47.
+ *
+ * <p>Attention: This class is intended for use in the testing phase only and will not be included
+ * in the final packaged artifact for production environment. For production environment, Spark will
+ * use its own NettyUtils instead of this one. This is somewhat of a hack, but given that Spark 2.x
+ * doesn't update frequently, it's not much of an issue to proceed this way.
  */
 public class NettyUtils {