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<Integer, String> newmap = new HashMap<Integer, String>();

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

    // get keyset value from map
    Set keyset = newmap.keySet();

    // check key set values
    System.out.println("Key set values are: " + keyset);
}

From source file:Main.java

public static void main(String[] argv) {
    Map map = new HashMap();

    map.put("Adobe", "Mountain View, CA");
    map.put("IBM", "White Plains, NY");
    map.put("Learning Tree", "Los Angeles, CA");

    Iterator k = map.keySet().iterator();
    while (k.hasNext()) {
        String key = (String) k.next();
        System.out.println("Key " + key + "; Value " + (String) map.get(key));
    }//w w  w  . j ava2s .c  om
}

From source file:Main.java

public static void main(String[] argv) throws Exception {
    Map map = new HashMap();
    for (Iterator it = map.values().iterator(); it.hasNext();) {
        Object value = it.next();
    }//from   w  w  w. j a va2  s.co  m
}

From source file:Main.java

public static void main(String[] argv) throws Exception {
    Map map = new HashMap();

    for (Iterator it = map.keySet().iterator(); it.hasNext();) {
        Object key = it.next();//from ww  w. j a  v a 2  s  .  c  o m
    }
}

From source file:Main.java

public static void main(String[] argv) throws Exception {
    Map map = new HashMap();
    for (Iterator it = map.entrySet().iterator(); it.hasNext();) {
        Map.Entry entry = (Map.Entry) it.next();
        Object key = entry.getKey();
        Object value = entry.getValue();
    }//  www. j a va2  s  .  c o  m
}

From source file:Main.java

public static void main(String[] args) {
    Map<String, String> map = new HashMap<String, String>();
    map.put("Pacific", "America/Los_Angeles");
    map.put("Mountain", "America/Denver");
    map.put("Central", "America/Chicago");
    map.put("Eastern", "America/New_York");
    ZoneId.of("Mountain", map);

}

From source file:Main.java

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

    for (int i = 0; i < 10; i++) {
        map.putIfAbsent(i, "val" + i);
    }//from   www. j a  va 2s  .co m

    map.forEach((id, val) -> System.out.println(val));

    map.computeIfPresent(3, (num, val) -> val + num);
    System.out.println(map.get(3)); // val33

    map.computeIfPresent(9, (num, val) -> null);
    System.out.println(map.containsKey(9)); // false

    map.computeIfAbsent(23, num -> "val" + num);
    System.out.println(map.containsKey(23)); // true

    map.computeIfAbsent(3, num -> "bam");
    System.out.println(map.get(3)); // val33
}

From source file:Main.java

public static void main(String[] args) {
    Map errors = new HashMap();

    errors.put("404", "A.");
    errors.put("403", "B.");
    errors.put("500", "C.");

    String errorDesc = (String) errors.get("404");
    System.out.println("Error 404: " + errorDesc);

    Iterator iterator = errors.keySet().iterator();
    while (iterator.hasNext()) {
        String key = (String) iterator.next();
        System.out.println("Error " + key + " means " + errors.get(key));
    }//w ww. j ava 2  s  . c o  m
}

From source file:Main.java

public static void main(String[] args) {
    Map<String, String> oldMap = new HashMap<String, String>();
    oldMap.put("a", "1");
    oldMap.put("A", "2");

    Map<String, String> newMap = new TreeMap<String, String>(String.CASE_INSENSITIVE_ORDER);
    newMap.putAll(oldMap);//from   w w  w  .java 2  s .co  m
    String value = newMap.get("a");
    System.out.println(value);
}

From source file:Main.java

public static void main(String[] a) {
    Map<String, String> yourMap = new HashMap<String, String>();
    yourMap.put("1", "one");
    yourMap.put("2", "two");
    yourMap.put("3", "three");

    Map<String, String> sortedMap = new TreeMap<String, String>(yourMap);

    System.out.println(sortedMap);
}