Evaluating expression in debugger

Class bellow compiles and runs fine under JDK1.6 but debugger evaluate window Alt+F8 fails to execute expression new TestLongBoxing(1L) is there different compiler been used for expression evaluation.

public class TestLongBoxing
{
    public TestLongBoxing(Long testLong)
    {
        System.out.println("OK");
    }


    public static void main(String[] args)
    {
        new TestLongBoxing(1L);
    }
}