NullPointerException when Creating an Array of objects

java arrays nullpointerexception

marjasin · Dec 17, 2009 · Viewed 50.1k times · Source

I have been trying to create an array of a class containing two values, but when I try to apply a value to the array I get a NullPointerException.

public class ResultList {
    public String name;
    public Object value;
}

public class Test {
    public static void main(String[] args){
        ResultList[] boll = new ResultList[5];
        boll[0].name = "iiii";
    }
}

Why am I getting this exception and how can I fix it?

Answer

You created the array but didn't put anything in it, so you have an array that contains 5 elements, all of which are null. You could add

boll[0] = new ResultList();

before the line where you set boll[0].name.