Introduction
Java, a widely-used programming language, has seen significant changes and improvements over the years. This article will highlight the most important changes in the Java Platform from Java 8 to Java 18.
Java 8 was launched in March 2014, and Java 18 was released in March 2022. Over these eight years, the Java Platform has seen 203 JDK Enhancement Proposals (JEPs), each bringing new features, improvements, and changes. Adopting these newer JDK versions brings numerous benefits but also presents challenges, especially for older applications compiled with older releases.
Key Changes and Improvements
While it's not possible to cover all 203 JEPs in this article, we'll focus on some of the most impactful changes that have shaped the Java Platform's evolution.
Lambda Expressions and Stream API (Java 8)
Java 8 introduced Lambda Expressions, a feature that brought functional programming to Java and made the code more readable and concise. Along with Lambda Expressions, the Stream API was introduced, providing a new abstraction that allows you to process data in a declarative way.
##language-java
List<String> names = Arrays.asList("John", "Jane", "Adam", "Eve");
names.stream()
.filter(name -> name.startsWith("A"))
.forEach(System.out::println);
Module System (Java 9)
Java 9 brought one of the most significant changes to the Java Platform - the introduction of the Module System, also known as Project Jigsaw. This feature allows developers to create modular applications with a better structure and improved performance.
##language-java
module com.example {
requires com.example.lib;
}
Local-Variable Type Inference (Java 10)
Java 10 introduced Local-Variable Type Inference, which allows developers to use the 'var' keyword to declare local variables. This feature enhances code readability and reduces boilerplate code.
##language-java
var list = new ArrayList<String>(); // infers ArrayList<String>
var stream = list.stream(); // infers Stream<String>
Switch Expressions (Java 12)
Java 12 introduced Switch Expressions as a preview feature, which was later finalized in Java 14. This feature simplifies the traditional switch statement, making it more flexible and less error-prone.
##language-java
switch (day) {
case MONDAY, FRIDAY, SUNDAY -> System.out.println(6);
case TUESDAY -> System.out.println(7);
case THURSDAY, SATURDAY -> System.out.println(8);
case WEDNESDAY -> System.out.println(9);
}
Records (Java 14)
Java 14 introduced Records as a preview feature, which was later finalized in Java 16. Records provide a compact syntax for declaring classes that are intended to be simple "data carriers".
##language-java
record Point(int x, int y) { }
Pattern Matching for instanceof (Java 16)
Java 16 introduced Pattern Matching for the 'instanceof' operator, which eliminates the need for explicit type casting and makes the code cleaner and safer.
##language-java
Object obj = "Hello";
if (obj instanceof String s) {
System.out.println(s.toLowerCase());
}
Conclusion
The evolution from Java 8 to Java 18 has brought numerous changes and improvements, making Java more powerful, flexible, and easier to use. However, adopting these new features can be challenging, especially for applications built with older Java versions. It's crucial to understand these changes and their impact to fully leverage the power of the Java Platform.
For more detailed information about these changes and other JEPs, consider exploring resources such as Dev.java and Oracle Java.
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