Java Options Class

https://www.youtube.com/watch?v=vKVzRbsMnTQ

• All Optional is a container , that either has something in it or it doesn't
• example : if you query something by name in DB it may or may not return something

think of it as a box with a label.

• if cat found in DB , then it fills Optional with that data
• if cat not found in DB then it it puts a null in optional to return Empty "Optional"

if you know for sure that thing you will put inside Optional is never null use OF instead , if null goes in below code exception is thrown

The way you return is above

Although end result is similar to first , but when user sees Optional it knows that it can expect it to be blank.

There is also

• orElseGet( ) : use a lambda to create unknown cat
• orElseThrow( ) : if optional is empty throw "noSuchElementException" ( similar to get( ) ) 

Get Age or else return 0

NOTE

• Optional is only meant to be used as a return type and nothing else
• do not overuse it