Question

Why does the split method not return an array with 2 elements?

for(int i = 0; i < temparray.size(); i++)
{
if (temparray.get(i).contains("_"))
    System.out.println("True" + temparray.get(i).length() + " " + temparray.get(i));
String[] temp = temparray.get(i).split("_");
System.out.println(temp[0]);
//System.out.println(temp[1]);
//friendsOld.add(new Friend(temp[0],temp[1]));
}

If I uncomment either of the lines, I get ArrayOutofBoundsException: 1. The println always returns True, the length of the String, and then a String with _ located within the String – NOT at the end.

I’ve tried negative parameters for .split(), converting the String to char arrays and breaking the String using indexOf() to find the location of _ then splitting it manually using substring(). There might be something wrong with the String itself but here is the code for the array of Strings: ArrayList<String> temparray = new ArrayList<String>();.

Answer 1

It seems that you forgot the braces after the if-statement:

if (temparray.get(i).contains("_")) {
    System.out.println("True" + temparray.get(i).length() + " " + temparray.get(i));
    String[] temp = temparray.get(i).split("_");
    System.out.println(temp[0]);
    System.out.println(temp[1]);
    friendsOld.add(new Friend(temp[0],temp[1]));
}

The way you wrote it, the string is splitted even when it doesn’t contain an underscore. Only the output of “True […]” is limited to strings containing one.

You should start using the debugger – it will display the values of variables when hitting an exception breakpoint allowing you to further track down the bugs in your code.