Fixed KeepAliveRunner for when service not yet set

examples/src/main/java/net/schmizz/sshj/examples/KeepAlive.java

@@ -0,0 +1,55 @@
+/**
+ * Copyright 2009 sshj contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package net.schmizz.sshj.examples;
+
+import net.schmizz.keepalive.KeepAliveProvider;
+import net.schmizz.sshj.DefaultConfig;
+import net.schmizz.sshj.SSHClient;
+import net.schmizz.sshj.common.IOUtils;
+import net.schmizz.sshj.connection.channel.direct.Session;
+import net.schmizz.sshj.connection.channel.direct.Session.Command;
+import net.schmizz.sshj.transport.verification.PromiscuousVerifier;
+
+import java.io.IOException;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+/** This examples demonstrates how to setup keep-alive to detect connection dropping. */
+public class KeepAlive {
+
+    public static void main(String... args)
+            throws IOException, InterruptedException {
+        DefaultConfig defaultConfig = new DefaultConfig();
+        defaultConfig.setKeepAliveProvider(KeepAliveProvider.KEEP_ALIVE);
+        final SSHClient ssh = new SSHClient(defaultConfig);
+        try {
+            ssh.addHostKeyVerifier(new PromiscuousVerifier());
+            ssh.connect(args[0]);
+            ssh.getConnection().getKeepAlive().setKeepAliveInterval(5); //every 60sec
+            ssh.authPassword(args[1], args[2]);
+            Session session = ssh.startSession();
+            session.allocateDefaultPTY();
+            new CountDownLatch(1).await();
+            try {
+                session.allocateDefaultPTY();
+            } finally {
+                session.close();
+            }
+        } finally {
+            ssh.disconnect();
+        }
+    }
+}