Java 17 Interview Questions and Answers

Ques 1. What is enhanced Pseudo-Random Number Generators in Java 17?

It offers a new interface type and solutions for pseudo-random number generators to make using multiple PRNG (Pseudo-Random Number Generators) algorithms simpler and properly support stream-based operations.

Example: RandomGeneratorFactory

public IntStream getPseudoVals(String algorithm, int streamSize) {    
    // returns an IntStream with size @streamSize of random numbers generated using the below @algorithm    
    // where the lower bound is 0 and the upper is 100 (exclusive)    
    return RandomGeneratorFactory.of(algorithm).create().ints(streamSize, 0,100);
}

Ques 2. What is the update on Vector API in Java 17?

The Vector API works with Single Instruction, Multiple Data / SIMD operations, which include multiple sets of instructions being processed concurrently. It uses specialized CPU hardware that provides vector instruction and enables the operation of these instructions as pipelines.

The new API will consequently give programmers the ability to write more effective code. It makes better use of the capabilities of the underlying hardware.

Few of the operations can be enhanced with Vector API: scientific algebra linear applications, image processing, character processing, and any heavy arithmetic application or any application that needs to apply an operation for multiple independent operands.

Ques 3. What are Deserialization Filters Based on Context in Java 17?

Firstly introduced by the JDK 9 version, makes it possible for us to verify receiving serialized data from untrusted sources, which is a frequent source of security problems.

In Java 17, applications can configure dynamically chosen and context-specific deserialization filters. Each deserialization operation will invoke such filters.

Ques 4. What is JDK Internals Encapsulate strongly in Java 17?

Since Java 17 new JEP 403 eliminates the flag -illegal-access, it signals a step toward strongly enclosing JDK internals.

If the flag is present and the platform will disregard the flag, then the console will send out a message to stop using the given flag.

This feature will prevent JDK users from accessing internal APIs, except for critical ones like sun.misc.Unsafe.

Ques 5. What is Foreign Functions and Memory API in Java 17?

Java programmers can retrieve code from outside the JVM. Thanks to the Foreign Function and Memory API, it controls memory outside of the heap.

The intention is to replace the JNI API and enhance its performance and security over the previous version.

Ques 6. What is Generate sealed Classes in Java 17?

Adds sealed classes and interfaces to the Java language to make it better. Sealed classes and interfaces limit other classes, and interfaces can extend and implement them, respectively.

Showing some other progress to pattern matching along with the JEP 406 will make it possible to check the type, cast, and act code pattern more sophisticatedly and cleanly.

public abstract sealed class Subjects  

permits English, Maths, Science {...}