This is a quick and dirty utility class to transform some keys that use dot notation (i.e. properties file keys) to a hierarchical structure like a java.util.Map. Usefull to transform a properties file to a json

DotNotationToMap.java

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

/*
* This is a quick and dirty utility class to transform some keys 
* that use dot notation (i.e. properties file keys) to a hierarchical 
* structure like a java.util.Map.
* Usefull to transform a properties file to a json.
*/
public class DotNotationToMap
{

/* returns {a: {
              b: {
                c: "uno",
                d: "due"
              },
              e: "tre"
            },
            f: "quattro"
          }
  */
    public Map<String, Object> example()
    {
        Map<String, Object> map = new HashMap<>();
        put(map, "a.b.c", "uno");
        put(map, "a.b.d", "due");
        put(map, "a.e", "tre");
        put(map, "f", "quattro");
        return map;
    }

    private void put(Map<String, Object> map, String path, String value)
    {
        String[] split = path.split("\\.");
        Map<String, Object> newMap = map;
        int i = 0;
        int n = split.length;
        for (String s : split)
        {
            if (i == n - 1)
            {
                newMap.put(s, value);
            } else
            {
                Object o = newMap.get(s);
                if (o == null)
                {
                    newMap.put(s, new HashMap<String, Object>());
                }
                newMap = (Map<String, Object>) newMap.get(s);
            }
            i++;
        }
    }

}