Black Box Testing : If one perform testing only on the functional part of an Application without having structural knowledge then that method of testing is known as Black box Testing. Usually it is done by Test engineer

White Box Testing : If one perform testing on the structural part of an application then that method of testing is known as 
White Box Testing.Usually it is done by Developers.
Ex:coding(Unit Testing)

Regards
Ram Mohan reddy

White box testing is done by the person who is having deeper
knowledge about the module and mostly this will be done by
Developers.
Example: Unit Testing

Black Box testing is done by the tester who is not having
deeper knowledge about software, only based on
specifications testing is done
Example: System Acceptance Testing

White Box Testing:- White box testing is based on knowledge
of the internal logic of an application's code. DIfferent
test that take place here are 
1. coverage of code statements
2. Branch testing
3. Path Tesitng
4. Condition checking testing.
5. Mutation Testing.

Both are done by Test Engineers but only difference is The
Tester who does Black Box Testing do have the knowledge of
coding part usually we take one of the developers as White
Box Test engineer.


Black Box Testing:- Black box testing is functional testing,
not based on any knowledge of internal software design or
code. Black box testing is based on requirements and
functionality.
 Different test that take place here are

1.Boundary value analysis and Equivalence testing
2. Error Guessing
3. Error Handling
4. Compactability testing
5. Parallel testing
6. Configuration Testing.

Apart from these we have lot.

Black Box Testing:- Black Box Testing is a System Testing.
Here we check the complete functionality of the application.
Here the tester does not examine the programming code and
does not need the knowledge of any coding standards. Here he
enters an input and check whether we are able to get the
exact output irrespective of what is happening in the code.
Here we have functional testing and non-functional testing.
Again both are of different concepts. 


 White Box Testing:- White Box Testing is non-system
testing. Here the tester should have the knowledge of coding
standards. Here we should review the entire coding part like
we should go through the statement coverage testing, branch
testing and loop testing, mean to say that we have to check
the complete coding standards and mainly here we do Mutation
testing (like we make some changes to the existing code and
run the code and check whether we are able to get any error
or not). This again has lot of subject to learn, can’t be
described but you have to refer to the books to get the
complete knowledge on it. For more clarification if you have
the book called “Art of Software testing” it will make u
clear on these topics.