Properties merge(Object, Object, BiFunction) in Java

merge(Object, Object, BiFunction): This method is available in java.util.Properties class of Java.

Syntax:

Object java.util.Properties.merge(Object key, Object value, BiFunction<? super Object, ? super Object, ?> remappingFunction)

This method takes three arguments. If the specified key is not already associated with a value or is associated with null, associate it with the given non-null value.

Parameters: Three parameters are required for this method.

key: key with which the resulting value is to be associated.

value: the non-null value to be merged with the existing value associated with the key or if no existing value or a null value is associated with the key, to be associated with the key.

remappingFunction: the remapping function to recompute a value if present.

Returns: the new value associated with the specified key, or null if no value is associated with the key.

Exceptions: NA

Approach

Java

import java.util.Properties;
import java.util.function.BiFunction;

public class Propertiesmerge {
    public static void main(String[] args) {

        Properties properties = new Properties();

        properties.put("Hello", "World");
        properties.put("C++", "Program");
        properties.put("Java", "Program");

        Object key = "Hello", value = "World";
        BiFunction<? super Object, ? super Object, 
               ?> remappingFunction = (a, b) -> a;
        System.out.println(properties.merge(key, 
                     value, remappingFunction));

    }
}

Output:

World