add SofaRejectedExecutionHandler for user-customized thread pool (#1450)

* add SofaRejectedExecutionHandler for user custom thread pool

* add RejectedExecutionHandler test case

* format code

* format code

Author: bohrqiu

core/api/src/main/java/com/alipay/sofa/rpc/server/UserThreadPool.java

@@ -113,6 +113,7 @@ protected Executor buildExecutor() {
         if (prestartAllCoreThreads) {
             threadPoolExecutor.prestartAllCoreThreads();
         }
+        threadPoolExecutor.setRejectedExecutionHandler(new SofaRejectedExecutionHandler());
         return threadPoolExecutor;
     }
 

core/api/src/test/java/com/alipay/sofa/rpc/config/UserThreadPoolManagerTest.java

@@ -18,10 +18,13 @@
 
 import com.alipay.sofa.rpc.server.UserThreadPool;
 import com.alipay.sofa.rpc.server.UserVirtualThreadPool;
+import com.alipay.sofa.rpc.server.SofaRejectedExecutionHandler;
 import org.junit.Assert;
 import org.junit.Test;
+
 import java.util.Set;
 import java.util.concurrent.Executor;
+import java.util.concurrent.RejectedExecutionHandler;
 import java.util.concurrent.ThreadPoolExecutor;
 
 public class UserThreadPoolManagerTest {
@@ -67,6 +70,16 @@ public void userThreadPoolBuildTest() {
         Assert.assertNull(result);
     }
 
+    @Test
+    public void testRejectedExecutionHandler() {
+        UserThreadPool userThreadPool = new UserThreadPool();
+        Executor executorService = userThreadPool.getUserExecutor();
+        Assert.assertTrue(executorService instanceof ThreadPoolExecutor);
+        RejectedExecutionHandler rejectedExecutionHandler = ((ThreadPoolExecutor) executorService)
+            .getRejectedExecutionHandler();
+        Assert.assertTrue(rejectedExecutionHandler instanceof SofaRejectedExecutionHandler);
+    }
+
     @Test
     public void userThreadPoolCompatibleTest() {
         UserThreadPool userThreadPool = new UserThreadPool();