Java 17 is a Long-Term Support (LTS) release with many modern language, JVM, and API improvements. Here are the most important features developers commonly use.
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Major Java 17 Features
Sealed Classes
Pattern Matching for switch
Records
Text Blocks
Enhanced instanceof
New Random Generator API
Foreign Function & Memory API
What is Sealed Classes?
Sealed classes were introduced in Java to provide controlled inheritance. Before sealed classes, if a class was public, any class could extend it. But sometimes we want to restrict which classes are allowed to inherit from a parent class.
Using the sealed keyword, we can explicitly define which subclasses are permitted to extend or implement a class or interface.
This improves:
better control over inheritance,
security,
maintainability,
and makes the code more predictable.
For example, in a payment system, if I have a Payment class, I may want only CreditCard, UPI, and…
