OptionalLong orElseThrow(Supplier) method in Java with examples

Last Updated : 27 May, 2019

The orElseThrow(Supplier) method of OptionalLong class is used to get the long value contained by OptionalLong. If a value is present, this method returns the value, otherwise, this method throws an exception produced by the exception supplying function. The exception Supplier function is passed as a parameter.

Syntax:

public <X extends Throwable> long 
    orElseThrow(Supplier<X> exceptionSupplier)
        throws X extends Throwable

Parameters: This method accepts one parameter exceptionSupplier which is the supplying function that produces an exception to be thrown.

Return value: This method returns the value, if present.

Exception: This method throw following Exceptions:

X – if no value is present.
NullPointerException – if no value is present and the exception supplying function is null
X extends Throwable

Below programs illustrate orElseThrow(Supplier) method:
Program 1:

// Java program to demonstrate 
// OptionalLong.orElseThrow(Supplier) method 
  
import java.util.OptionalLong; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // create a OptionalLong 
        OptionalLong opLong = OptionalLong.of(894763545123L); 
  
        // apply orElseThrow(Supplier) 
        long value = opLong.orElseThrow(ArithmeticException::new); 
  
        System.out.println("value " + value); 
    } 
} 

Output:

Program 2:

// Java program to demonstrate 
// OptionalLong.orElseThrow(Supplier) method 
  
import java.io.IOException; 
import java.util.OptionalLong; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // create a OptionalLong 
        OptionalLong opLong = OptionalLong.empty(); 
  
        // apply orElseThrow(Supplier) 
        Long value; 
  
        try { 
  
            value = opLong.orElseThrow(ArithmeticException::new); 
        } 
        catch (ArithmeticException e) { 
            // TODO Auto-generated catch block 
            System.out.println("Exception " + e); 
        } 
    } 
} 