If your HashMap is returning actual Java Date objects, then you need: Date result = map.get(key); Otherwise you will get a class cast exception (and if your HashMap is using generics, you would get a compile time exception). Check out the HashMap API. SCJP6Is...
with some valuesHashMap<String,Integer>map=newHashMap<String,Integer>();map.put("Monday",5);map.put("Tuesday",6);map.put("Wednesday",10);// Invoke keySet() on the HashMap object to get the keys as a setSet<String>keys=map.keySet();for(String key:keys){System.out.println(key);...
import java.util.HashMap; import java.util.Map; import java.util.Scanner; /** * Java Program to to check if a key exists in HashMap or not. * This example uses containsKey() method to search for a key in HashMap. * * @author WINDOWS 8 */ public class KeySearchDemo { public sta...
Sort the Keyset Using theTreeMapClass in Java Below is the code block to demonstrate the sorting of aHashMapby its key. importjava.util.HashMap;importjava.util.Map;importjava.util.TreeMap;publicclassHashMapSortByKey{publicstaticvoidmain(String[]args){Map<String,String>map=newHashMap<>();ma...
In this tutorial, we'll take a look at how to sort a HashMap by key in Java. Let's go ahead and create a simple HashMap: Map<String, Integer> unsortedMap = new HashMap(); unsortedMap.put("John", 21); unsortedMap.put("Maria", 34); unsortedMap.put("Mark", 31); unsortedMap...
Loop through the items of a HashMap with a for-each loop.Note: Use the keySet() method if you only want the keys, and use the values() method if you only want the values:ExampleGet your own Java Server // Print keys for (String i : capitalCities.keySet()) { System.out.println(...
In this article we show how to use Java HashMap collection. HashMap is a container that stores key-value pairs. Each key is associated with one value. Keys in a HashMap must be unique. HashMap is called an associative array or a dictionary in other programming languages. HashMaps take ...
How to check value existence in a HashMap Check key existence containsKey(Object key) checks to see if the HashMap has that key import java.util.HashMap; //from jav a 2s . co m public class Main { public static void main(String[] args) { HashMap<String, String> hMap = new Hash...
import java.util.HashMap; //from ww w . ja v a 2 s . c o m public class Main { public static void main(String args[]) { HashMap<Integer, Integer> map = new HashMap<Integer, Integer>(); map.put(1, 2); map.put(2, 3); map.put(3, 4); for (Integer key : map.keySet...
Loop through the items of a HashMap with a for-each loop.Note: Use the keySet() method if you only want the keys, and use the values() method if you only want the values:Example // Print keys for (String i : capitalCities.keySet()) { System.out.println(i); } Try it ...