Why is it ok to do "new" to an abstract class?

Question

In the following code, i was thinking there would be an error because of the line "new Calculate" because it is an abstract class. Why is this code working?

abstract class Calculate
{
  abstract int multiply(int a, int b);
}

public class Main
{
  public static void main(String[]args)
 {
   int result = new Calculate()
   {
        @Override
        int multiply(int a, int b)
        {
           return a*b;
        }
   }   .multiply(12,32);
 }
}