Can i use MyMain as class name ?

Answer 1

You can use almost any name for your class name or any other name you use. The only exceptions are language keywords and reserved words are forbidded.

Answer 2

Only the reserved words are reserved for no use. You can use any word as a class name.

here you can find the list-
https://www.computerhope.com/jargon/j/java_reserved_words.htm