JVM

Regardless of the level of Java practitioner, the JVM is a hurdle to climb. The JVM is a must in any job or interview. If you don’t understand the JVM, it can be very detrimental in terms of salary (nearly 70% of candidates are attached to the JVM)

This paper introduces the JVM in detail about threads, memory model, JVM runtime memory, garbage collection and algorithm, four reference types in Java, GC generational collection algorithm VS partition collection algorithm, GC garbage collector, Java IO/NIO, JVM class loading mechanism.

Basic Concepts:

The JVM is an imaginary computer that can run Java code, including a set of bytecode instructions, a set of registers, a stack, a garbage collection, a heap, and a storage method field. The JVM runs on top of the operating system and has no direct interaction with the hardware.

Too many detailed knowledge points, too long copy can be seen ** Java Core Knowledge System **

The JVM directory

Java collection

In general, our program needs to know how many objects to create based on when the program is running. But until the program runs and develops, we don’t know exactly how many objects we need, or even the exact type. To meet these general programming needs, we want to be able to create any number of objects at any time, anywhere. What will hold these objects? Arrays come to mind first, but arrays can only hold data of a uniform type, and their length is fixed. What then? The assembly was born!

1. Interface inheritance and implementation

2, the List

3, Set

4, the Map

Java collection framework diagram

** Java Core Knowledge System ** has a detailed breakdown version of set graph corresponding to each knowledge point (see table of contents).

Java multithreaded concurrency

Let’s start with the concurrent knowledge base architecture diagram:

Java thread implementation/creation?

Four thread pools?

Thread life cycle (state)

There are four ways to terminate a thread

What’s the difference between sleep and wait?

The difference between start and run?

Java background thread

Java lock

Basic threading methods

Thread context switch

Synchronous locks and deadlocks

Thread Pool Principle

Java blocking queue principle

CyclicBarrier, CountDownLatch, Semaphore

The role of the volatile keyword (variable visibility, disallow reordering)

How do I share data between two threads?

ThreadLocal (ThreadLocal storage)

The difference between synchronized and ReentrantLock

ConcurrentHashMap concurrent

Thread scheduling used in Java

Process scheduling algorithm

The concept and characteristics of threads

** Java Core Knowledge System ** has a detailed breakdown version of set graph corresponding to each knowledge point (see table of contents).

Deep analysis of spring principle

Spring is being adopted by more and more microservices practitioners for its many benefits, and mastering it will make you a leader in rapid application development. This article will help you understand the mechanics behind Spring from the perspective of its source code and core implementation principles.

catalog

The characteristics of the Spring

Spring’s core components

Common Spring modules

Spring is mainly package

Spring Spring

Principle of the Spring IOC

Spring APO principle

Spring MVC principles

Spring Boot principle

JPA principle

Mybatis cache

Tomcat architecture

** Java Core Knowledge System ** has a detailed breakdown version of set graph corresponding to each knowledge point (see table of contents).

How to obtain ** Core Knowledge **

Principle of the spring

Micro service

Micro service is now the Internet industry you have to master the knowledge point, is also the most popular one of the most popular knowledge, let’s look together!

Service Registration Discovery

API gateway

Configuration center

Service tracking

Service fusing

API management

** Java Core Knowledge System ** has a detailed breakdown version of set graph corresponding to each knowledge point (see table of contents).

How to obtain ** Core Knowledge **

Because the text is too long, I will not introduce it here. Other core knowledge include Netty and RPC, network, log, Zookeeper, Kafka, RabbitMQ, Hbase, MongoDB, and Cassandra , 24 design patterns, load balancing, database, consistency algorithm, Java algorithm, data structure, distributed cache and so on.

This knowledge system is suitable for all Java programmers to learn, there are detailed explanations and introductions about the knowledge points in the above directory, master all the content of the knowledge points will have a qualitative improvement for you, which also summarizes a lot of questions encountered in the interview process and have the corresponding answer summary.

Forward this article to follow me scan below for claim