FULL PRODUCT VERSION :
java 1.8_66

ADDITIONAL OS VERSION INFORMATION :
Widnows 7 64bits

A DESCRIPTION OF THE PROBLEM :
The same operations performed on Calendar instance produce different result if the getTime() method is called between steps (check the test case).

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run the test case.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Fri Aug 05 15:21:03 CEST 2016
Fri Aug 05 15:21:03 CEST 2016
ACTUAL -
Performing the same operations in the same order ends with different dates:

Fri Aug 05 15:21:03 CEST 2016
Fri Jul 15 15:21:03 CEST 2016

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
        Calendar cal = Calendar.getInstance();
        cal.set(Calendar.MONTH,6);
        cal.set(Calendar.DAY_OF_MONTH,1);
        cal.set(Calendar.DAY_OF_WEEK,Calendar.FRIDAY);
        cal.add(Calendar.WEEK_OF_MONTH,2);
        System.out.println(cal.getTime());

        cal = Calendar.getInstance();
        cal.set(Calendar.MONTH,6);
        cal.set(Calendar.DAY_OF_MONTH,1);
        cal.getTime(); //<---- here is the difference between blocks
        cal.set(Calendar.DAY_OF_WEEK,Calendar.FRIDAY);
        cal.add(Calendar.WEEK_OF_MONTH,2);
        System.out.println(cal.getTime());
---------- END SOURCE ----------