Java HashMap

In Java, HashMap is a widely used data structure that belongs to the Java Collections Framework. It is part of the java.util package and provides an efficient way to store and retrieve key-value pairs.

A HashMap allows you to associate keys with values and quickly retrieve values based on their keys.

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Tutorials

Java Map computeIfAbsent()

The Map.computeIfAbsent() method computes the mapped value for a key using a mapping function if the specified key does not exist in the Map or is mapped to a null value. It has been added as the default method in the Map interface in Java 8. 1. When to Use the computeIfAbsent() …

Java Map

Maps in Java are the core building blocks of the Collections framework. These tutorials will teach the basics of working with different maps.

Java Nested Map with Examples

A nested Map is Map inside another Map. Learn to create a nested HashMap and add, remove and iterate over the elements with examples.

Clone a HashMap – Shallow and Deep Copy

Learn to create clone of a HashMap in Java. We will see the java programs to create shallow copy and deep copy of a HashMap. 1. Creating a Shallow Copy of Map We can create a shallow copy of a given HashMap in two ways. The first uses the clone() …

How to Join or Merge Two Maps in Java

Learn merging two hashmaps in both cases – ignoring duplicate keys (overwrites the value) or handling duplicate keys. 1. Merge Two HashMaps Ignoring Duplicate Keys This one is a simple solution. Use firstMap.putAll(secondMap) method that copies all of the mappings from the secondMap to firstMap. As we know hashmap does …

How to Compare Two Maps in Java

Learn to compare two Java Maps for the equality of their entries, key and values, and find the Map differences using Guava’s MapDifference API.

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