The Java.AtomicLong.getAndUpdate() method is an inbuilt method, which updates the current value of the object by applying the specified operation on the current value. It takes an object of LongUnaryOperator interface as its parameter and applies the operation specified in the object to the current value. It returns the previous value.
Syntax:
public final long getAndUpdate(LongUnaryOperator function)
Parameters: This method accepts as parameter an LongUnaryOperator function.
It applies the given function to the current value of the object.
Return Value: The function returns the previous value of the object.
Example to demonstrate the function.
import java.util.concurrent.atomic.AtomicLong;import java.util.function.LongUnaryOperator;  public class Demo {    public static void main(String[] args)    {        // AtomicLong initialized with a value of -20000        AtomicLong al = new AtomicLong(-20000);          // Unary operator defined to negate the value        LongUnaryOperator unaryOperator = (x) -> - x;          // Function called and the unary operator        // is passed as an argument        long x = al.getAndUpdate(unaryOperator);        System.out.println("Previous value is " + x);        System.out.println("Updated Value is " + al);    }} |
Output:
Previous Value is -20000 Updated value is 20000
Reference: https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/atomic/AtomicLong.html
