How to do a null check? Like if its in a 'if' statement. Plus what data types do support null

Question

is default constraint available in Java?

Answer 1

if(myVar == null) {
// Throw exception? set default value? etc.
}

// Your code

_

All type that derives from the class object do.
Primitives do not. here is the list with so background to them: https://docs.oracle.com/javase/tutorial/java/nutsandbolts/datatypes.html

Answer 2

does this work on a double?

Answer 3

doubles can't be null, their default value is 0 except that Double type allows nulls.

Answer 4

I'm making a simple interest calc. what to do if I want that if no value is entered in time field the default is 1?

Answer 5

Double myVar = get value from user
if myVar equals null set myVar to 1

Answer 6

thanks dude!