Fixed Failing EchoTest (#782)

core-java/src/main/java/com/baeldung/java/nio/selector/EchoClient.java

@@ -17,6 +17,11 @@ public class EchoClient {
         return instance;
     }
 
+    public static void stop() throws IOException {
+        client.close();
+        buffer = null;
+    }
+
     private EchoClient() {
         try {
             client = SocketChannel.open(new InetSocketAddress("localhost", 5454));
@@ -42,5 +47,4 @@ public class EchoClient {
         return response;
 
     }
-
 }

core-java/src/main/java/com/baeldung/java/nio/selector/EchoServer.java

@@ -1,21 +1,19 @@
 package com.baeldung.java.nio.selector;
 
+import java.io.File;
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.nio.ByteBuffer;
+import java.nio.channels.SelectionKey;
+import java.nio.channels.Selector;
 import java.nio.channels.ServerSocketChannel;
 import java.nio.channels.SocketChannel;
-import java.nio.channels.Selector;
-import java.nio.channels.SelectionKey;
-import java.nio.ByteBuffer;
-import java.io.IOException;
-import java.util.Set;
 import java.util.Iterator;
-import java.net.InetSocketAddress;
-import java.io.File;
+import java.util.Set;
 
 public class EchoServer {
 
-    public static void main(String[] args)
-
-            throws IOException {
+    public static void main(String[] args) throws IOException {
         Selector selector = Selector.open();
         ServerSocketChannel serverSocket = ServerSocketChannel.open();
         serverSocket.bind(new InetSocketAddress("localhost", 5454));
@@ -49,7 +47,6 @@ public class EchoServer {
         }
     }
 
-
     public static Process start() throws IOException, InterruptedException {
         String javaHome = System.getProperty("java.home");
         String javaBin = javaHome + File.separator + "bin" + File.separator + "java";

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();
     }
 }