Java don't let me to use isEmpty

[manic mauve]

I declared a OptionalDouble as a marix, and I can't to use a if with isEmpty for this:

if (polEXP_Lim[f][c].isEmpty()){

}

All of this obviously inside of two for's

Marks me the error in isEmpty.

A way to solve it or an alternative to isEmpty?

[mint crown]

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[mint crown]

Please format your code to make it more readable.
For java, it should look like this:
```​​​`​java
public void foo() {

}
​​​`​```