Here is what I came up with, 
import java.util.*;
class Rotate
{
    int transitionPoint(int arr[],int n)
    {
        int low =0,high =n-1;
           int mid = 0;
           while(low<=high)
           {
               mid = low+high/2;
               if(arr[mid]==0)
               {
                   if(arr[mid+1]==1)
                     return (mid+1);
                   low=mid+1;
               }
               if(arr[mid]==1)
               {
                   if(arr[mid-1]==0)
                      return (mid+1);
                   high = mid-1;
               }
           }
           return mid;
        }
}
class TransitionPoint
{ 
    public static void main(String args[])
    {
        Scanner sc = new Scanner(System.in);
        int n =sc.nextInt();
        int arr[]=new int[n];
        for(int i=0;i<n;i++)
        {
            arr[i] = sc.nextInt();
        }
        Rotate obj = new Rotate();
        System.out.println(obj.transitionPoint(arr,n));
        }   
    }
}
Hope this will help.