When a Java program is in java.lang.Math.sin() ( actually SharedRuntime::dsin() ) AsyncGetCallTrace is unable to trace the Java callstack and returns zero
frames.

% cat foo.java
public class foo {
       public static void main(String args[]) {
               int i;
               double a = 0.0;

               for (i = 0; i < 10000000; i++)
                       a += 0.001 * java.lang.Math.sin(0.001 * i);

               System.out.println(a);
       }
}