Dear!Plzz Plzzz I am very worried,And I am very Sad,Because I am student JAVA OOPS?

I am studen of Univeristy,I am doing BSCS ,And I am in 2nd semster,,,My performance in midterm in all subject is good but JAVA OOPS is not,,,,,,I have no concepts about JAVA OOPS,,,i HAVE not able to make LOGIC of JAVA OOPS programs,,,,,,My number in java oops is Only 5 out of 18,,,,,Plzzzzz plzzzzz I am much much worried,,,,,,Can Any friend help me in java oops,,,How I Build logic in JAVA Progrms....Plzzzzzzzzzzzzzz plzzzzzzzzzzzzz

Oracle has a good tutorial on Java Object Oriented Programming (OOP) here:

http://docs.oracle.com/javase/tutorial/java/concepts/