Problem with processing.net

I am using Processing together with an Arduino Yun. Most of the time it works fine, each even second I make measurements with the Arduino and each even minute i send a request from Processing to the Arduino to send me the mean of the last measurements. But sometimes it happens that Processing hangs.I get a "myClient" which is not "null", but a timeout! But when I make a "myClient. write" command after a "if (myClient != null)" I get directly a "NullPointerException"!

Here the important part of my code with the error message:

Main Program

297  // Get Client Anfang!
298  if((second() == 0) && (minute()%intervallMessung == 0) && !connected)
299  {
300    clientTime = true;
301    timeOut = 0;
302  }
303
304  if (clientTime) getClient();
305
306  if (connected && !sent) sendClient();

Method getClient

319  public void getClient()
320  {
321    fehler = false;
322    if (ausdruck)
323    {
324      print(nf(hour(),2) + ":" + nf(minute(),2) + ":" + nf(second(),2));
325      println(" Client Anfrage");
326    }
327    myClient = new Client(this, "192.168.2.162", 5555);
328    if (myClient != null)
329    {
330      if (ausdruck)
331      {
332        print(nf(hour(),2) + ":" + nf(minute(),2) + ":" + nf(second(),2));
333        println(" Client verbunden" + myClient);
334      }
335      connected = true;
336      clientTime = false;
337    } else {
338      if (ausdruck)
339      {
340        print(nf(hour(),2) + ":" + nf(minute(),2) + ":" + nf(second(),2));
341        println(" Client nicht verbunden : " + myClient);
342      }
343      fehler = true;
344      clientTime = false;
345    }
346  }

Output getClient

15:02:00 Client Anfrage
java.net.ConnectException: Operation timed out
    at java.net.PlainSocketImpl.socketConnect(Native Method)
    at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339)
    at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
    at java.net.Socket.connect(Socket.java:579)
    at java.net.Socket.connect(Socket.java:528)
    at java.net.Socket.(Socket.java:425)
    at java.net.Socket.(Socket.java:208)
    at processing.net.Client.(Unknown Source)
    at Wetterstation.getClient(Wetterstation.java:327)
    at Wetterstation.draw(Wetterstation.java:304)
    at processing.core.PApplet.handleDraw(PApplet.java:2306)
    at processing.core.PGraphicsJava2D.requestDraw(PGraphicsJava2D.java:243)
    at processing.core.PApplet.run(PApplet.java:2177)
    at java.lang.Thread.run(Thread.java:744)
15:03:15 Client verbunden : processing.net.Client@154c40f5

Obviously everything OK because "myClient != null" But I got an timeout message! How can I than detect an ConnectException? Normally with the "try" "Catch" method! But that doesn't work! So, because the program doesn't know anything about an exception the method sendClient is started.

method sendClient

349  public void sendClient()
350  {
351    if (timeOut < 60)
352    {
353      if (ausdruck)
354      {
355        print(nf(hour(),2) + ":" + nf(minute(),2) + ":" + nf(second(),2));
356        println(" Vor myClient.write" + myClient);
357      }
358      if ( myClient != null)
359      {
360        myClient.write("\n");
361        if (ausdruck)
362        {
363          print(nf(hour(),2) + ":" + nf(minute(),2) + ":" + nf(second(),2));
364          println(" Nach myClient.write");
365        }
366        gesendet = true;
367      } else {
368        println("NullPointer um " + nf(hour(),2) + ":" + nf(minute(),2) + ":" + nf(second(),2));
369        println("Client nicht verbunden");
370        timeOut = second();
371      }
372    } else
373    {
374      fehler = true;
375      gesendet = false;
376    }
377  }

Obviously nothing OK
myClient = null!!!! although the if statement was true!
Why is myClient null after after an if (myClient != null) statement ?

15:03:15 Vor myClient.write : processing.net.Client@154c40f5
java.lang.NullPointerException
    at processing.net.Client.write(Unknown Source)
    at processing.net.Client.write(Unknown Source)
    at Wetterstation.sendClient(Wetterstation.java:360)
    at Wetterstation.draw(Wetterstation.java:306)
    at processing.core.PApplet.handleDraw(PApplet.java:2306)
    at processing.core.PGraphicsJava2D.requestDraw(PGraphicsJava2D.java:243)
    at processing.core.PApplet.run(PApplet.java:2177)
    at java.lang.Thread.run(Thread.java:744)
15:03:15 Nach myClient.write : processing.net.Client@154c40f5

Why is it not possible to detect exceptions with the "try" and "catch" method? In Java is that the normal method.