I ran your code as-is (Windows 10 64-bit, Java SE 1.8.0_45) and got this:
Student ID :s-111
Student Name :Durga
Student Address :Hyd
Student Course Details
Course ID :C-333
Course Name :JAVA
Your error suggests that the value of crs, which is the same as the value of a was null (which would the case if the annotation was not present). Perform a check before you start using the reference to the annotation to make sure it is not equal to null.
Also, you might want to tried building and running from the command line rather than thr IDE to see if any additional warnings or errors are reported.