Java - Check Not Null for a number, else assign default string value

Question

I am looking for a way to set the default value of a variable depending on whether a value is null or not.

The value in question is a double, and the default value (if that value is null) should be a string.

I tried using the following way but it failed because .orElse expects a double (aka same data type as "value"). Is there any Java methods that I can use to achieve that?

Double value = 8.0;
Optional.ofNullable(value).orElse("not found")

Answer 1

You are not far, just map the value:

String strDouble = Optional.ofNullable(value).map(Objects::toString).orElse("not found");

Answer 2

Since the left side of the the assignment operator can be either a Double or a String, the best that can be done is to specify its type as Object.

This will work:

Object value2 = Optional.<Object>ofNullable(value).orElse("not found");

(i.e. The only shared class in the class hierarchy for Double and String is Object)