index out of bounds exception java [duplicate]

Answer 1

java.lang.IndexOutOfBoundsException: Index: 0, Size: 0

ArrayList is empty. It does not contain any element.

Index: 0, Size: 0.

You are trying to access it.So you are getting IndexOutOfBoundsException.

if(r.size() == 0) && r.size() < pointer + 1)   //If ArrayList size is zero then simply return from method.
  return;

Answer 2

You are passing in an empty array. You should do some validation on the inputs

if (r == null || r.size()==0){
   throw new RuntimeException("Invalid ArrayList");
}

Answer 3

Your array size is 0, you should initialize it correctly in order to iterate it.