strange problem in an array

I'm working on a little server app with Java. So, I'm getting informations from different client, and if information comes in, the following method is called:

public void writeToArray(String data) {
    data = trim(data);
    String[] netInput = new String[5];
    netInput[0]="a";
    netInp开发者_运维知识库ut[1]="a";
    netInput[2]="a";
    netInput[3]="a";
    netInput[4]="a";
    netInput = split(data, ",");
    pos_arr = PApplet.parseInt(netInput[0]);
    rohr_value = PApplet.parseInt(netInput[1]); // THIS LINE KICKS OUT THE ERROR.
    if(pos_arr >0 && pos_arr<100) {
        fernrohre[pos_arr] = rohr_value;
        println("pos arr length: " + fernrohre[pos_arr]);
        println("pos arr: " + pos_arr);
    }

The console on OS X gives me the following error:

Exception in thread "Animation Thread"
java.lang.ArrayIndexOutOfBoundsException:1
 at server_app.writeToArray(server_app.java:108) at server_app.draw(server_app.java:97)
 at processing.core.PApplet.handleDraw(PApplet.java:1606)
 at processing.core.PApplet.run(PApplet.java:1503)
 at java.lang.Thread.run(Thread.java:637)

As you can see, I tried to fill the array netInput with at least 5 entries, so there can't be an ArrayIndexOutOfBoundsException.

I don't understand that, and I'm thankful for your help!

It would work already for me, if I can catch the error and keep the app continuing.

---

You put 5 Strings into the array, but then undo all your good work with this line;

netInput = split(data, ",");

data obviously doesn't have any commas in it.

---

In this line

netInput = split(data, ",");

your array is being reinitialized. Your split method probably returns an array with only 1 element (I can guess that data string doesn't contain any ",").

---

Update

The split() method is custom, not String.split. It too needs to be checked to see what is going wrong. Thanks @Carlos for pointing it out.

Original Answer

Consider this line:

netInput = split(data, ",");

This will split the data string using comma as a separator. It will return an array of (number of commas + 1) resulting elements. If your string has no commas, you'll get a single element array.

Apparently your input string doesn't have any commas. This will result in a single element array (first element aka index = 0 will be the string itself). Consequently when you try to index the 2nd element (index = 1) it raises an exception.

---

You need some defensive code,

if(netInput.length > 1)
   pos_arr = PApplet.parseInt(netInput[0]);
   rohr_value = PApplet.parseInt(netInput[1]); 

---

You make netInput = split(data, ","); and
split(data, ",");

returns one element array

---

You are re-assigning your netInput variable when the split() method is called.

The new value might not have an array count of 5.

Can you provide the source for the split() method?