Java HashMap: Understanding How It Works Internally
Java HashMap is one of the most commonly used data structures in Java programming. It is a part of the Java Collections Framework and is used to store key-value pairs. In this blog post, we will discuss how HashMap works internally, including its implementation, recent changes in the latest Java versions, and its usage.
Before we dive into the internal working of HashMap, let’s take a brief look at its history. The first version of HashMap was introduced in Java 1.2. Since then, it has undergone several changes and improvements, including changes in its internal implementation. The latest version of Java, Java 17, includes some significant improvements to the HashMap class.
Recent Changes
In Java 8, the HashMap class was modified to use a balanced tree instead of a linked list to store key-value pairs when there are too many collisions. This modification improved the performance of HashMap for large sets of data. In Java 9, a new factory method was introduced to create immutable maps using the Map.of() method. In Java 11, the HashMap class was modified to support var keyword, and in Java 14, a new method called computeIfAbsent() was added to the HashMap class to make it easier to compute values for a given key.
Why Use HashMap?
