Exploring Java’s Hidden Gems: Lesser-Known Features You Should Know About.”


Java is a powerful and versatile programming language that has been around for over two decades. It has evolved significantly over the years, with new features and enhancements being added in each release. While some features are well-known and commonly used, there are many lesser-known features that can make development faster and more efficient. In this blog post, we’ll explore some of Java’s hidden gems – lesser-known features that you should know about.

  1. Local Variable Type Inference:

Introduced in Java 10, local variable type inference allows developers to declare variables without specifying their types. Instead, the type is inferred from the expression used to initialize the variable. This feature can reduce boilerplate code, improve readability, and make code easier to maintain.

For example, instead of writing:

Map<String, List<Integer>> myMap = new HashMap<String, List<Integer>>();

We can write:

var myMap = new HashMap<String, List<Integer>>();
  1. Switch Expressions:

Switch statements have been around in Java since its early days, but they were limited to using constant expressions as case labels. Java 12 introduced switch expressions, which allow developers to use more powerful expressions as case labels, including lambdas and method references.

For example:

int result = switch (day) {
    case "Monday", "Tuesday", "Wednesday", "Thursday", "Friday" -> 1;
    case "Saturday", "Sunday" -> 0;
    default -> throw new IllegalArgumentException("Invalid day: " + day);
  1. Java Flight Recorder:

Java Flight Recorder (JFR) is a tool that collects detailed information about the Java Virtual Machine (JVM) at runtime. It can be used to diagnose performance problems, memory leaks, and other issues. JFR was previously only available in the commercial version of Java, but it was made open-source in Java 11.

To enable JFR, add the following JVM options:

-XX:+UnlockCommercialFeatures -XX:+FlightRecorder
  1. Compact Strings:

Java 9 introduced a new feature called “compact strings,” which changes the way strings are stored in memory. Before Java 9, each character in a string was stored as a 16-bit Unicode value, regardless of whether the string contained only ASCII characters. With compact strings, ASCII strings are stored in a more memory-efficient format, using a single byte per character.

  1. JShell:

JShell is an interactive shell that allows developers to experiment with Java code in a REPL (Read-Evaluate-Print Loop) environment. JShell was introduced in Java 9 and provides a fast and easy way to test and debug Java code.


Java has been around for over two decades and has evolved significantly over the years. While some features are well-known and commonly used, there are many lesser-known features that can make development faster and more efficient. Local variable type inference, switch expressions, Java Flight Recorder, compact strings, and JShell are just a few of Java’s hidden gems that developers should be aware of. By taking advantage of these features, developers can write more efficient and effective Java code.

Leave a Reply