Java 17 面试题与答案

问题 1. What is Java 17 or Java 17 in nutshell?

The another long-term support(LTS) release for the Java SE platform is Java 17 LTS. The previous LTS version was Java 11. Under the Oracle No-Fee Terms and Conditions License, JDK 17 binaries are free to use in production and redistribute at no cost with the help of OpenJDK. LTS stands for long-term support. It is available from September, 2021. For OracleJDK it is mandatory to purchase the license but it is absolutely free to use OpenJDK.

问题 2. What is the difference between Oracle JDK and OpenJDK?

To check the detail difference, please check here: OracleJDK vs OpenJDK 💯💯

问题 3. What are the JDK17 new features?

The new features added in Java 17 are as follows:

• Restore or Rebuild the "Always-Strict Floating-Point" Semantics
• Enhanced faster the "pseudo-Random" Number Generators
• New macOS rendering pipelines
• macOS/AArch64 Port
• Dismiss the Applet API for Removal
• JDK Internals Encapsulate strongly
• Switch Pattern Matching (Preview)
• Activation of the Removal RMI
• Generate sealed Classes
• Removal of the Experimental AOT and JIT Compiler
• Remove the Security Manager.
• Foreign Functions and Memory API (Incubator)
• Vector API (Second Incubator)
• Deserialization Filters Based on Context (content-specific)

问题 4. What is Restore or Rebuild the "Always-Strict Floating-Point" Semantics in Java 17?

This JEP makes floating-point operations uniformly stringent and is primarily intended for scientific applications. Both default floating-point operations, strict or strictfp, provide the same outcomes for calculations using floating-point on every platform.

问题 5. 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);
}