The isPresent() method of java.util.Optional class in Java is used to find out if there is a value present in this Optional instance. If there is no value present in this Optional instance, then this method returns false, else true.
Syntax:
public boolean isPresent()
Parameters: This method do not accept any parameter.
Return value: This method returns a boolean value stating whether if there is a value present in this Optional instance.
Below programs illustrate isPresent() method:
Program 1:
import java.util.*;
public class GFG {
public static void main(String[] args)
{
Optional<Integer> op
= Optional.of(9455);
System.out.println("Optional: "
+ op);
System.out.println("Is any value present: "
+ op.isPresent());
}
}
Output:
Optional: Optional[9455] Is any value present: true
Program 2:
import java.util.*;
public class GFG {
public static void main(String[] args)
{
Optional<Integer> op
= Optional.empty();
System.out.println("Optional: "
+ op);
try {
System.out.println("Is any value present: "
+ op.isPresent());
}
catch (Exception e) {
System.out.println(e);
}
}
}
Output:
Optional: Optional.empty Is any value present: false
Reference: https://docs.oracle.com/javase/9/docs/api/java/util/Optional.html#isPresent–
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