Modify error handling with exception handling

[diptangsu]

For example, for the file Stack.java, pushing into a full-stack is prevented by an if-else block, change all such occurrences with user-defined exceptions.

[lelloman]

Hi, I'd like to pick this one up for hacktoberfest. I'm not entirely sure I understood what you mean by "user-defined exceptions". I was thinking to throw specific RuntimeException, to follow your example, defining a FullStackException extends RuntimeException and throw an instance of that. Would it be OK?

[diptangsu]

@lelloman ofcourse.

[lelloman]

Great thanks, then I'm gonna do it :)