How do you calculate log base 2 in Java for integers?

Question

I use the following function to calculate log base 2 for integers:

public static int log2(int n){
    if(n <= 0) throw new IllegalArgumentException();
            


        

Answer 1

Some cases just worked when I used Math.log10:

public static double log2(int n)
{
    return (Math.log10(n) / Math.log10(2));
}