In my previous post we have learnt How to Sort HashMap in Java by Keys, in this article we will learn to sort HashMap values. We will be using the below three approaches. Implementing the Comparator Interface along with TreeMap Collection Implementing a separate class implementing Comparator Interface Using Collections.sort() method … [Read more...]
How to Sort HashMap in Java by Keys
We all know that HashMap will not save key-value pairs in any sort of order neither preserve the insertion order. In this tutorial we will learn how to sort a HashMap based on Keys. We will be using two approaches. TreeMap Collection class (Which has in-built support for sorting the elements using Comparable and Comparator Interface) Implementing the Comparator … [Read more...]
Java HashMap values() Method Example
The values() method of java.util.HashMap class returns a Collection view of the values contained in this map. The collection is backed by the map, so changes to the map are reflected in the collection, and vice-versa. … [Read more...]
Java HashMap size() Example
The size() method of java.util.HashMap class will returns the number of key-value mappings in this map. … [Read more...]
Java HashMap remove(Object o) Method Example
The remove(Object o) method will remove the mapping for the specified key from this map if present. … [Read more...]
Java HashMap putAll(Map m) Example
The put(K key, V value) method of java.util.HashMap class associates the specified value with the specified key in this map. If the map previously contained a mapping for the key, the old value is replaced whereas putAll(Map<? extends K,? extends V> m) method copies all of the mappings from the specified map to this map. These mappings will replace any mappings that this … [Read more...]
Java HashMap put(K key, V value) Example
The put(K key, V value) method of java.util.HashMap class associates the specified value with the specified key in this map. If the map previously contained a mapping for the key, the old value is replaced. … [Read more...]
Java HashMap keySet() Example
The keySet() method of java.util.HashMap class returns a Set view of the keys contained in this map. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. … [Read more...]
Java HashMap isEmpty() Example
The isEmpty() method of java.util.HashMap class will tests if the HashMap has any elements or not. … [Read more...]
Java HashMap get(Object key) Example
The get(Object key) method of java.util.HashMap class returns the value to which the specified key is mapped, or null if this map contains no mapping for the key. … [Read more...]
Java HashMap entrySet() Example
The entrySet() method of java.util.HashMap class returns a Set view of the mappings contained in this map. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. … [Read more...]
Java HashMap containsValue(Object value) Example
The containsKey(Object key) method of java.util.HashMap class returns true if this map contains a mapping for the specified key where as containsValue(Object value) method returns true if this map maps one or more keys to the specified value. … [Read more...]
