Greatest of three numbers (java)

[joefreddiecheeran]

Please review and merge PR #409 . This is for Hacktoberfest. Thank you :)

[shivani2190]

Assign this task to me

[ABHINAV0307]

Can you assign this to me ?

[GauraviVeling]

Hello. Please can you assign this issue to me. I can swap numbers normally as well as using functions.