Optional of() method in Java with examples
Last Updated :
30 Jul, 2019
The of() method of java.util.Optional class in Java is used to get an instance of this Optional class with the specified value of the specified type.
Syntax:
public static <T>
Optional<T> of(T value)
Parameters: This method accepts value as parameter of type T to create an Optional instance with this value.
Return value: This method returns an instance of this Optional class with the specified value of the specified type.
Exception: This method throws NullPointerException if the specified value is null.
Below programs illustrate of() 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);
}
}
|
Output:
Optional: Optional[9455]
Program 2:
import java.util.*;
public class GFG {
public static void main(String[] args)
{
try {
Optional<Integer> op
= Optional.of( null );
System.out.println( "Optional: "
+ op);
}
catch (Exception e) {
System.out.println(e);
}
}
}
|
Output:
java.lang.NullPointerException
Reference: https://docs.oracle.com/javase/9/docs/api/java/util/Optional.html#of-T-
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