Java 9: Null check can be replaced with method call.

Author: fbacchella

src/main/java/zmq/io/mechanism/curve/CurveServerMechanism.java

@@ -4,6 +4,7 @@
 import static zmq.io.Metadata.SOCKET_TYPE;
 
 import java.nio.ByteBuffer;
+import java.util.Objects;
 
 import zmq.Msg;
 import zmq.Options;
@@ -510,12 +511,7 @@ private int produceError(Msg msg)
         assert (statusCode == null || statusCode.length() == 3);
 
         msg.putShortString("ERROR");
-        if (statusCode != null) {
-            msg.putShortString(statusCode);
-        }
-        else {
-            msg.putShortString("");
-        }
+        msg.putShortString(Objects.requireNonNullElse(statusCode, ""));
 
         return 0;
     }

src/test/java/guide/clone.java

@@ -2,6 +2,7 @@
 
 import java.util.HashMap;
 import java.util.Map;
+import java.util.Objects;
 
 import org.zeromq.*;
 import org.zeromq.ZMQ.Poller;
@@ -206,9 +207,7 @@ else if (command.equals("CONNECT")) {
             else if (command.equals("GET")) {
                 String key = msg.popString();
                 String value = kvmap.get(key);
-                if (value != null)
-                    pipe.send(value);
-                else pipe.send("");
+                pipe.send(Objects.requireNonNullElse(value, ""));
             }
             msg.destroy();