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

Udemy Course Discounted Link

If you want to participate in Mock Interview send your nominations using the below google form

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.

---

### 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.

Mock Interview Playlist:

Java 8 Interview Questions and Answers:

Hibernate Interview Questions and Answers:

Spring Boot Interview Questions and Answers:

Angular Playlist:

Subscriber and Follow Code Decode

#springboot3 #codedecode #interviewquestions

[mangeshkhandare]

Where to access the docs you were referring to? Please make it available in google drive or open access platform.

[anaghabide]

Most awaited video.. Thanks for sharing. Can you one on Java 21? also on Java 8 to Java 17 up gradation?

[Kashi_nivashi]

Thanks a lot for this Video. I have been appearing for the interviews and now at least having the knowledge of java 17 is expected from the interviewer.

[maheshgnayak]

Literally getting this question in all interviews

[sayanbiswas]

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

[jaydeepkk]

hi. i tried to purchase the udemy course but the discounted code seems to be not available anymore. do you have anymore codes?

[anamikatripathi]

Mam you videos are not organised properly. It takes so much time to find videos on tour channel can you arrange them in order please.

[jeevan.explore]

Can you share the documents link ? If possible ?

[tilakbossh]

Yes it is fixed now thanks a lot for the same❤❤

[kinb]

Java 17 is 2 years old now, please request to share java 21 and 23 new features.

[FarmCode]

Hi that project course is for what much years of experience???!

[BhagyashreeDembla]

Mam just a suggestion please don't mind. If you keep saying too much of a theory and don't waste your time. It is actually wasting time and I forget the concept a lot after listening to these phrases. A humble request please don't add such phrases. It is hard to remember things u just told if you urself are saying such things. When I try to recall things I recall these phrases more rather then the real concept.

[himanshunahak]

Hi mam,
Im preparingfor my intreviw got to know about channel
I completed java 8 playlist it was very helpful and it helped me a lot

Thankyou for making such a helpful video 🌸

[nishroop]

Can you share the documents link ? If possible ?