Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0 in map

Question

I have the next problem to compile using NetBeans and console in Ubuntu 14.04:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0

My code is (in the line of error):

Object maxFreK = map.keySet().toArray()[0];

How can I solve it?

Thanks!

Answer 1

java.lang.ArrayIndexOutOfBoundsException : 0 means that your array doesn't contain any elements.
It is an empty array.

You can use somenthing like this:

Object maxFreK=null; 
if (!map.isEmpty()){
  maxFreK = map.keySet().toArray()[0];
}

Answer 2

This exception shows that your map is empty and your are accessing the first key which is not present. Before accessing any element from the keyset, check if the array/keyset contains elements

for e.g.

Object [] objArr = map.keySet().toArray();
if(objArr.length>0){
   Object maxFreK = objArr [0];
}