ByReference.java

package examples;

import java.util.HashMap;
import java.util.Map;

public class ByReference {

 public static void main(String[] args) {
 Map<String, String> map = new HashMap<>();
 map.put("key1", "value1");

 ConfigHolder configHolder = new ConfigHolder(map);
 System.out.println("The config is : " + configHolder.getConfig());
 map.put("key2", "value2");
 System.out.println("The config after modifying the initial map : " + configHolder.getConfig());
 }

 static class ConfigHolder {
 private final Map<String, String> conf;


 ConfigHolder(Map<String, String> conf) {
 this.conf = conf;
 }

 public Map<String, String> getConfig() {
 return conf;
 }
 }

}