【Java Interview】Take you an in-depth analysis from the interviewer's point of view, what is a Java virtual machine and why should it be used?

"What is the Java Virtual Machine and why should I use it".

Recently, a classmate with 1-year Java development experience went to interview Ali and asked me for help when he encountered this problem.

Hello everyone, I'm Mic, a Java programmer for 14 years.

So, what is the interviewer looking for in this question?

Problem Analysis

The Java Virtual Machine is the platform on which Java applications run.

For many beginners, the first step is basically learning how to write code, without paying attention to the platform on which the Java code runs.

Therefore, although I have been writing code for several years, my understanding of Java itself is not deep enough. Once there is a problem with the program, it is difficult to troubleshoot and solve it.

The starting point for the interviewer to examine this question, I think there are three

• Understand the depth of the job seeker's understanding of the Java language, which will help improve the quality of code writing
• Understand the job seeker's mastery of JVM basics. A good foundation can help quickly solve GC problems, memory problems, etc.
• Investigate the potential of job seekers, a person who has a passion for technology, helps to better accompany the growth of the company

Therefore, for this problem, we only need to cut into the explanation from the perspective of the key features of JVM Write Once and Run Anywhere.

Let's take a look at how experts should answer.

Expert:

The Java virtual machine is the runtime environment of the Java language.

The reason why the Java virtual machine is needed is to provide the Write Once and Run Anywhere capabilities for the Java language.

In fact, the ability to write once, run everywhere is impossible by itself. Because of different operating systems and hardware.

The final executed instructions will vary greatly.

The Java virtual machine solves this problem. It can generate machine instructions that conform to this platform according to different operating systems and hardware differences.

Simply understood, it is equivalent to a translation tool. Under the window, it is translated into the executable instructions of the window, and under the linux, it is translated into the executable instructions under the linux.

In addition to this factor, I think the function of automatic garbage collection is also one of the reasons, which allows developers to save the work of garbage collection.

Reduces the complexity of program development.

Summarize

Well, today's sharing ends here

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