JUCX: Do not delete reference to listener connHandler (v.1.10.x)

NEWS

@@ -12,6 +12,7 @@
 * Fix Infiniband port speed detection for HDR100
 * Fix build issues in gtest-all.cc and sock.c with GCC11
 * Fix performance degradation with cuda memory on self endpoint
+* Fix bug in JUCX listener connection handler.
 
 ## 1.10.0 (March 9, 2021)
 ### Features:

bindings/java/src/main/java/org/openucx/jucx/ucp/UcpListener.java

@@ -17,13 +17,18 @@
 public class UcpListener extends UcxNativeStruct implements Closeable {
 
     private InetSocketAddress address;
+    private UcpListenerConnectionHandler connectionHandler;
 
     public UcpListener(UcpWorker worker, UcpListenerParams params) {
         if (params.getSockAddr() == null) {
             throw new UcxException("UcpListenerParams.sockAddr must be non-null.");
         }
+        if (params.connectionHandler == null) {
+            throw new UcxException("Connection handler must be set");
+        }
+        this.connectionHandler = params.connectionHandler;
+        this.address = params.getSockAddr();
         setNativeId(createUcpListener(params, worker.getNativeId()));
-        address = params.getSockAddr();
     }
 
     /**

bindings/java/src/main/java/org/openucx/jucx/ucp/UcpListenerParams.java

@@ -14,12 +14,13 @@ public class UcpListenerParams extends UcxParams {
     public UcpListenerParams clear() {
         super.clear();
         sockAddr = null;
+        connectionHandler = null;
         return this;
     }
 
     private InetSocketAddress sockAddr;
 
-    private UcpListenerConnectionHandler connectionHandler;
+    UcpListenerConnectionHandler connectionHandler;
 
     /**
      *  An address, on which {@link UcpListener} would bind.

bindings/java/src/main/native/jucx_common_def.cc

@@ -338,7 +338,6 @@ void jucx_connection_handler(ucp_conn_request_h conn_request, void *arg)
     jmethodID on_conn_request = env->GetMethodID(jucx_conn_hndl_cls, "onConnectionRequest",
                                        "(Lorg/openucx/jucx/ucp/UcpConnectionRequest;)V");
     env->CallVoidMethod(jucx_conn_handler, on_conn_request, jucx_conn_request);
-    env->DeleteGlobalRef(jucx_conn_handler);
 }
 
 

bindings/java/src/main/native/listener.cc

@@ -44,7 +44,7 @@ Java_org_openucx_jucx_ucp_UcpListener_createUcpListener(JNIEnv *env, jclass cls,
         field = env->GetFieldID(jucx_listener_param_class,
                                 "connectionHandler", "Lorg/openucx/jucx/ucp/UcpListenerConnectionHandler;");
         jobject jucx_conn_handler = env->GetObjectField(ucp_listener_params, field);
-        params.conn_handler.arg = env->NewGlobalRef(jucx_conn_handler);
+        params.conn_handler.arg = env->NewWeakGlobalRef(jucx_conn_handler);
         params.conn_handler.cb = jucx_connection_handler;
     }
 

bindings/java/src/test/java/org/openucx/jucx/UcpListenerTest.java

@@ -114,14 +114,32 @@ public void testConnectionHandler() throws Exception {
         UcpEndpoint serverToClient = serverWorker2.newEndpoint(
             new UcpEndpointParams().setConnectionRequest(conRequest.get()));
 
-        // Temporary workaround until new connection establishment protocol in UCX.
+        // Test connection handler persists
         for (int i = 0; i < 10; i++) {
-            serverWorker1.progress();
-            serverWorker2.progress();
-            clientWorker.progress();
-            try {
-                Thread.sleep(10);
-            } catch (Exception ignored) { }
+            conRequest.set(null);
+            UcpEndpoint tmpEp = clientWorker.newEndpoint(new UcpEndpointParams()
+                .setSocketAddress(listener.getAddress()).setPeerErrorHandlingMode()
+                .setErrorHandler((ep, status, errorMsg) -> {
+
+                }));
+
+            while (conRequest.get() == null) {
+                serverWorker1.progress();
+                serverWorker2.progress();
+                clientWorker.progress();
+            }
+
+            UcpEndpoint tmpEp2 = serverWorker2.newEndpoint(
+                new UcpEndpointParams().setConnectionRequest(conRequest.get()));
+
+            UcpRequest close1 = tmpEp.closeNonBlockingFlush();
+            UcpRequest close2 = tmpEp2.closeNonBlockingFlush();
+
+            while (!close1.isCompleted() || !close2.isCompleted()) {
+                serverWorker1.progress();
+                serverWorker2.progress();
+                clientWorker.progress();
+            }
         }
 
         UcpRequest sent = serverToClient.sendStreamNonBlocking(