Language used to submit the code, making the difference.. Why???

Recently I have noticed that if I submit some code in Java it gives TLE/Wrong Ans, but when I submit the same code(logic) in C/Cpp the submission is successful. I don’t understand why is this happening.

Same we got with c#/c++. I guess it was all about slow I/O operations we have in c#, but yeah this is not fair at all.