How to solve java.lang.NullPointerException.

Question

this exception is throw in array initialization.

Answer 1

https://stackoverflow.com/questions/218384/what-is-a-nullpointerexception-and-how-do-i-fix-it

Answer 2

NullPointerExceptions are exceptions that occur when you try to use a reference that points to no location in memory (null) as though it were referencing an object. Calling a method on a null reference or trying to access a field of a null reference will trigger a NullPointerException.

For example,

String s = null;
int len = s.length(); // NullPointerException because s is null

So you should check if the variable is null before calling any method on it, for example:

int len;
if (s == null) {
len = 0;
}
else {
len = s.length(); // safe, s is never null when you get here
}

http://net-informations.com/java/cjava/null.htm