1 Program is a set of precise instructions telling a computer what to do.
2 It is like building your maze and then getting lost in it. Programming requires skill in controlling complexity, so code does not go out of control in such complexity, that no one understands it. The principle of KISS applies here. The simpler the better.
3 Programming language helps the programmer talk to the computer, on what actions it has to take, on a higher level. A language helps simplify and understand what the code is trying to do, so the programmer can understand.
4 It is a different language. Java was the result of marketing considerations, but not good judgment.