Viewing Sub Maps : TreeMap « Collections « Java Tutorial

1. Java Tutorial
2. Collections
3. TreeMap

SortedSet headMap(Object toKey)
SortedSet tailMap(Object fromKey)
SortedSet subMap(Object fromKey, Object toKey)

fromKey <= map keys < toKey

If you want to include the sub map, you must pass in value that is beyond it. If the element is a string, this can be done by appending something to the element: \0

Map headMap = map.headMap(toKey+"\0");

import java.util.Map;
import java.util.TreeMap;

public class MainClass {
  public static void main(String[] a) {

    TreeMap map = new TreeMap();
    map.put("key1", "value1");
    map.put("key2", "value2");
    map.put("key3", "value3");

    Map map2 = map.headMap("key2");
    System.out.println(map2);
  }
}

{key1=value1}