Fixed Failing EchoTest (#782)

core-java/src/test/java/com/baeldung/java/nio/selector/NioEchoIntegrationTest.java

@@ -4,19 +4,32 @@ import static org.junit.Assert.assertEquals;
 
 import java.io.IOException;
 
+import org.junit.After;
+import org.junit.Before;
 import org.junit.Test;
 
 public class NioEchoIntegrationTest {
 
+    Process server;
+    EchoClient client;
+
+    @Before
+    public void setup() throws IOException, InterruptedException {
+        server = EchoServer.start();
+        client = EchoClient.start();
+    }
+
     @Test
-    public void givenClient_whenServerEchosMessage_thenCorrect() throws IOException, InterruptedException {
-        Process process = EchoServer.start();
-        EchoClient client = EchoClient.start();
+    public void givenServerClient_whenServerEchosMessage_thenCorrect() {
         String resp1 = client.sendMessage("hello");
         String resp2 = client.sendMessage("world");
         assertEquals("hello", resp1);
         assertEquals("world", resp2);
+    }
 
-        process.destroy();
+    @After
+    public void teardown() throws IOException {
+        server.destroy();
+        EchoClient.stop();
     }
 }