How to check if array element is null to avoid NullPointerException in Java

Question

I have a partially nfilled array of objects, and when I iterate through them I tried to check to see whether the selected object is null before I do other stuff

Answer 1

You have more going on than you said. I ran the following expanded test from your example:

public class test {

    public static void main(String[] args) {
        Object[][] someArray = new Object[5][];
        someArray[0] = new Object[10];
        someArray[1] = null;
        someArray[2] = new Object[1];
        someArray[3] = null;
        someArray[4] = new Object[5];

        for (int i=0; i<=someArray.length-1; i++) {
            if (someArray[i] != null) {
                System.out.println("not null");
            } else {
                System.out.println("null");
            }
        }
    }
}

and got the expected output:

$ /cygdrive/c/Program\ Files/Java/jdk1.6.0_03/bin/java -cp . test
not null
null
not null
null
not null

Are you possibly trying to check the lengths of someArray[index]?