Java 17 new features with examples | Java 17 Interview Questions and Answers | Code Decode

In this video of code decode we have covered top java 17 feature interview questions and answers for fresher and experienced canditate
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Java 17, released in September 2021, is a long-term support (LTS) release, meaning it will receive extended support and updates for several years. This version introduced several important features and enhancements, many of which improve performance, security, and maintainability. Here's a rundown of some of the notable features and changes in Java 17:
1. Sealed Classes (JEP 409)
✅ What are Sealed Classes?
Sealed classes restrict which other classes can extend or implement them.
Unlike `final` , which blocks inheritance completely ❌
Unlike `abstract` , which allows any class to extend it ✅
Sealed classes allow only specific subclasses to extend them 🔒
Now in JDK 17, Sealed Classes are being finalized with no changes from JDK 16.
🔹 Why Use Sealed Classes?
Better control over class hierarchies.
Prevents unauthorized subclassing.
Improves maintainability in large projects.
#### 2. Pattern Matching for Switch (Preview) (JEP 406)
Introduced in Java 17 as a preview feature, Pattern Matching for `switch` improves `switch` statements by:
Simplifying type checking (No more `instanceof` + casting)
Allowing complex data structures (Records, Enums, etc.)
Reducing boilerplate code
Problem with Traditional `switch` (Before Java 17)
Before Java 17, `switch` only worked with:
Primitive types (`int` , `char` )
Enums
Strings
It did NOT support objects or type checks.
For example, to handle different types of objects, you had to write verbose code like this
Restore Always-Strict Floating-Point Semantics (JEP 306)
🔹 JEP 306 - Restore Always-Strict Floating-Point Semantics
JEP 306 was introduced to make floating-point arithmetic more predictable and consistent across platforms. It aims to restore strict floating-point semantics to avoid platform-specific discrepancies that could occur in earlier Java versions. This is especially important when the same code can give different results depending on the hardware or operating system.
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The Problem (Before JEP 306)
Floating-point operations in Java were sometimes optimized by the CPU or the JVM for performance.
Some CPUs (e.g., x86) used 80-bit registers (higher precision) in hardware, while others (e.g., ARM) used only 64-bit registers, leading to inconsistent behavior between platforms.
As a result, calculations involving floating-point numbers could yield different results on different hardware, even with the same Java code.
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[@sayanbiswas8847]

Thank you so much for this video team. Faced this question in one recent interview.