title: sonar runner showing http://localhost:9000 can not be reached
body: <p>I am facing the issue after successful installing sonarqube and sonar runner. 
  When I run in project /sonar-runner it is showing error.
  Anyone can help ?</p>
  
  <pre>ERROR: Sonar server 'http://localhost:9000' can not be reached
  INFO: ------------------------------------------------------------------------
  INFO: EXECUTION FAILURE
  INFO: ------------------------------------------------------------------------
  Total time: 0.109s
  Final Memory: 0M/87M
  INFO: ------------------------------------------------------------------------
  ERROR: Error during Sonar runner execution
  org.sonar.runner.kevinsawicki.HttpRequest$HttpRequestException: java.net.ConnectException: Connection refused at org.sonar.runner.kevinsawicki.HttpRequest.code(HttpRequest.java:1392)
  at org.sonar.runner.kevinsawicki.HttpRequest.ok(HttpRequest.java:1417)
  at org.sonar.runner.impl.ServerConnection.downloadString(ServerConnection.java:93) at org.sonar.runner.impl.ServerVersion.downloadVersion(ServerVersion.java:47)
  at org.sonar.runner.impl.ServerVersion.version(ServerVersion.java:38)
  at org.sonar.runner.impl.ServerVersion.is37Compatible(ServerVersion.java:58)
  at org.sonar.runner.impl.JarDownloader.checkVersionAndDownload(JarDownloader.java:36) at org.sonar.runner.impl.BatchLauncher$1.run(BatchLauncher.java:71) at java.security.AccessController.doPrivileged(Native Method) at org.sonar.runner.impl.BatchLauncher.doExecute(BatchLauncher.java:69) at org.sonar.runner.impl.BatchLauncher.execute(BatchLauncher.java:50) at org.sonar.runner.api.EmbeddedRunner.doExecute(EmbeddedRunner.java:102)
  at org.sonar.runner.api.Runner.execute(Runner.java:100) at org.sonar.runner.Main.executeTask(Main.java:70)  at org.sonar.runner.Main.execute(Main.java:59)  at org.sonar.runner.Main.main(Main.java:53) Caused by: java.net.ConnectException: Connection refused
  at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
  at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:534) at sun.net.www.protocol.http.HttpURLConnection$6.run(HttpURLConnection.java:1548) at sun.net.www.protocol.http.HttpURLConnection$6.run(HttpURLConnection.java:1544) at java.security.AccessController.doPrivileged(Native Method) at sun.net.www.protocol.http.HttpURLConnection.getChainedException(HttpURLConnection.java:1542) at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1193) at java.net.HttpURLConnection.getResponseCode(HttpURLConnection.java:397) at org.sonar.runner.kevinsawicki.HttpRequest.code(HttpRequest.java:1390) ... 15 more
  </pre>
  
  <p>Below mention sonar log is:</p>
  
  <pre>
      --> Wrapper Started as Daemon
  Launching a JVM...
  Wrapper (Version 3.2.3) http://wrapper.tanukisoftware.org
    Copyright 1999-2006 Tanuki Software, Inc.  All Rights Reserved.
  
  WrapperSimpleApp: Unable to locate the class org.sonar.application.App: java.lang.UnsupportedClassVersionError: org/sonar/application/App : Unsupported major.minor version 51.0
  
  WrapperSimpleApp Usage:
    java org.tanukisoftware.wrapper.WrapperSimpleApp {app_class} [app_arguments]
  
  Where:
    app_class:      The fully qualified class name of the application to run.
    app_arguments:  The arguments that would normally be passed to the
                    application.
  </pre>