Java.lang.object error

[G. Graz]

I am bit confused on a part of code that I am working on. I am grabbing ArrayList data and then putting it into an Array to compute the average value of that Array , I keep on getting the following error message " Operator cannot be applied to double, java.lang.object" during my sum += average[i], Anyway the way I have the loop structured should be correct , I do not know what I am missing to cause the error ? Any ideas ? Thank you.

public Double average (ArrayList<Double> score)
    {
       
        Object[] average = score.toArray();
        double sum = 0.0;
        for (int i = 0; i < average.length; i++)
        { 
          sum += average[i];
        }
   
     }

[Christophe Verré]

score is an ArrayList of Double, isn't it. Look at the API for ArrayList#toArray. Why did you declare the average array as an array of Object ?

[G. Graz]

ok, thank you ! I got it ! I was a bit confused by the API when I first looked at it . Thank you again.