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This article mainly explains the "JVM-related knowledge points", the content of the explanation is simple and clear, easy to learn and understand, the following please follow the editor's ideas slowly in depth, together to study and learn "what are the JVM-related knowledge points"!

JVM is the foundation on which java runs, and it's hard to believe that people who don't know anything about JVM can get a good understanding of java.

When I interview developers with more than 3 years of Java experience, JVM is almost a must-ask question.

Of course, JVM is not the only interview question that determines the quality of technical skills, but it can prove the level of java development ability.

In the big category of JVM, I think the knowledge that needs to be mastered are:

JVM memory model and structure

GC principle, performance tuning

Tuning: Thread Dump, analyzing memory structure

Class binary bytecode structure, class loader architecture, class loading process, instance creation process

Method execution process

New features provided by updates to major versions of Java (simple understanding is required)

2. Operation of Java

This may seem simple, but who can't run a java program?

But most of the time, we simply execute java programs through IDE. How does the underlying IDE execute java programs? A lot of people don't understand.

This knowledge is the most basic java developers need to master, the first is to teach you how to execute java programs on the command line, but many people once they have finished learning java and using IDE, they forget all about it.

Why is it important to know this? after knowing the purest startup mode of java, you can analyze the number of directories started at that time, how to name the execution, how to name the parameters, and whether there are any defects when something goes wrong with the startup.

This will help you to solve strange and possibly environment-related problems in your real development.

The knowledge that needs to be mastered here are:

Javac compiles java files to class files

The use of the java command and how to start the java class with package on the command line

The various paths (classpath, java) involved in the java program. Library . Path, home directory where java is running, etc.)

3. Data type (emphasis)

There is not much to say about this, but the mastery of basic types and object types in Java.

You can learn more about how JDK converts automatically, including packing and unpacking, and pay attention to avoiding the judgment of type equality after packing.

Main knowledge points:

Basic types: int, long, float, double, boolean.

Corresponding object types: conversion from Integer type to basic type, boxing and unboxing

Object type: equals, hashcode

Characteristics of String type

4. Objects and Instanc

In this respect, developers need to understand the concepts and differences between class and instance, which is a foundation of java's object-oriented features.

The main knowledge points are:

The concept of Class and Instance

The process of creating Instance:

No inheritance: allocate memory space, initialize variables, call constructors

There is inheritance: handle static actions, allocate memory space, define variables as initial values, from base class-> subclasses, handle initialization at definitions, execute constructors

Points to pay attention to:

Static properties are initialized from the base class-> subclass

Properties related to the default no-parameter construction method

5. access control

This is also a basis of java packaging features, need to master: public protected default private for class, method, field modification.

6. Process control

The basics of Java process control, although some grammars are not necessarily very common, need to be understood and used where appropriate.

Need to master: if, switch, loop, for, while and other process control syntax.

7. The concept of object-oriented programming (focus)

This is a core concept of java and needs to be mastered by any java developer.

Many features or knowledge points in Java are related to java object-oriented programming concepts.

As far as I understand it, a good developer needs to know more than these features (knowledge points) themselves.

It is also necessary to know how these objects are reflected in the object-oriented programming concept of java, which is more helpful for developers to master the development language java, as well as other object-oriented programming languages.

Here is just a brief list, the main knowledge points include:

Three object-oriented features: encapsulation, inheritance, and polymorphism

Thank you for your reading, the above is the content of "what are the knowledge points related to JVM". After the study of this article, I believe you have a deeper understanding of what the knowledge points related to JVM have, and the specific use needs to be verified in practice. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!

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