Example usage for java.util HashMap HashMap

Introduction

In this page you can find the example usage for java.util HashMap HashMap.

Prototype

public HashMap()

Source Link

Document

Constructs an empty HashMap with the default initial capacity (16) and the default load factor (0.75).

Usage

From source file:Main.java

public static void main(String[] args) {
    HashMap<String, String> hm = new HashMap<String, String>();
    hm.put("4", "four");
    hm.put("3", "three");
    hm.put("1", "one");
    hm.put("2", "two");

    Map<String, String> treeMap = new TreeMap<String, String>(hm);
    System.out.println(treeMap);//from   w  w w .  j a v a  2  s.c  o m
}

From source file:Main.java

public static void main(String args[]) {
    // create two hash maps

    HashMap<Integer, String> newmap1 = new HashMap<Integer, String>();
    HashMap<Integer, String> newmap2 = new HashMap<Integer, String>();

    // populate hash map
    newmap1.put(1, "tutorials");
    newmap1.put(2, "from");
    newmap1.put(3, "java2s.com");

    // clone 1st map
    newmap2 = (HashMap) newmap1.clone();

    System.out.println("1st Map: " + newmap1);
    System.out.println("Cloned 2nd Map: " + newmap2);
}

From source file:Main.java

public static void main(String[] args) {
    Map<String, String> map = new HashMap<>();
    map.put("CSS", "style");
    map.put("HTML", "mark up");
    map.put("Oracle", "database");
    map.put("XML", "data");

    // Get the entry Set
    Set<Map.Entry<String, String>> entries = map.entrySet();

    entries.forEach((Map.Entry<String, String> entry) -> {
        String key = entry.getKey();
        String value = entry.getValue();
        System.out.println("key=" + key + ",  value=" + value);
    });/*from www  . j  a  v  a  2s .  c om*/

}

From source file:Main.java

public static void main(String[] args) {
    TreeMap<Integer, String> db = new HashMap<Integer, String>();
    db.put(1000, "1000");
    db.put(1011, "1011");
    db.put(1102, "1102");
    db.put(2023, "2023");
    db.put(2034, "2034");

    TreeMap<Integer, String> db2 = new TreeMap<Integer, String>(db);

    System.out.println(db2);//  ww  w.j av  a 2s. c  o  m
}

From source file:Main.java

public static void main(String[] args) {

    HashMap<String, String> hashmap = new HashMap<String, String>();

    hashmap.put("one", "1");
    hashmap.put("two", "2");
    hashmap.put("three", "3");
    hashmap.put("four", "4");
    hashmap.put("five", "5");
    hashmap.put("six", "6");

    Iterator<String> keyIterator = hashmap.keySet().iterator();
    Iterator<String> valueIterator = hashmap.values().iterator();

    while (keyIterator.hasNext()) {
        System.out.println("key: " + keyIterator.next());
    }/*from  www .  jav a 2 s.c o m*/

    while (valueIterator.hasNext()) {
        System.out.println("value: " + valueIterator.next());
    }
}

From source file:Main.java

public static void main(String[] args) {
    WeakHashMap<String, String> hashMap = new HashMap<String, String>();

    hashMap.put("1", "first");
    hashMap.put("2", "two");
    hashMap.put("3", "from java2s.com");
    Map<String, String> weakHashMap = new WeakHashMap<String, String>(hashMap);
}

From source file:Main.java

public static void main(String[] args) {
    Map<String, Integer> map = new HashMap<String, Integer>();
    // add some values in the map
    map.put("One", 1);
    map.put("Two", 2);
    map.put("Three", 3);

    LinkedHashMap<String, Integer> linkMap = new LinkedHashMap<String, Integer>(map);

    System.out.println(linkMap);// w  ww .j a v  a2 s . co m

}

From source file:Main.java

public static void main(String[] args) {
    HashMap<String, Integer> myMap = new HashMap<String, Integer>();

    myMap.put("a", 1);
    myMap.put("b", 2);
    myMap.put("c", 3);

    Set<String> stStrKeys = myMap.keySet();
    Iterator<String> itrs = stStrKeys.iterator();
    while (itrs.hasNext()) {
        String s = itrs.next();//from w  ww  .j  a va2  s.co  m
        System.out.println(s + ": " + myMap.get(s));
    }
}

From source file:Main.java

public static void main(String args[]) {

    HashMap<String, String> hmap = new HashMap<String, String>();

    hmap.put("1", "A");
    hmap.put("2", "B");
    hmap.put("3", "C");
    hmap.put("4", "from java2s.com");

    // get typesafe view of the map
    Map<String, String> tsmap = Collections.checkedMap(hmap, String.class, String.class);

    System.out.println(tsmap);// w  ww  .j a v  a  2 s. c o  m
}

From source file:MainClass.java

public static void main(String[] a) {
    Map map = new HashMap();
    map.put("key1", "value1");
    map.put("key2", "value2");
    map.put("key3", "value3");
    map.put(null, null);/*from  w  ww  .j a  v a 2s.co m*/

    Set set = map.keySet();

    Iterator iter = set.iterator();

    while (iter.hasNext()) {
        System.out.println(iter.next());
    }
}