1. Basic JVM
JVM memory structure
Difference between heap, stack, method area, direct memory, heap and stack
Java memory model
memory visibility, reordering, sequential consistency, volatile, locking, final
garbage collection
Memory allocation strategy, garbage collector (G1), GC algorithm, GC parameters, determination of object survival
JVM parameters and tuning
Java Object Model
oop-klass, object header
HotSpot
Just-in-time compiler, compilation optimization
class loading mechanism
classLoader, class loading process, parent delegation (destroy parent delegation), modularity (jboss modules, osgi, jigsaw)
Virtual Machine Performance Monitoring and Troubleshooting Tools
jps, jstack, jmap、jstat, jconsole, jinfo, jhat, javap, btrace、TProfiler
Compile and decompile
javac 、javap 、jad 、CRF
Java Basics
read the source code
String、Integer、Long、Enum、BigDecimal、ThreadLocal、ClassLoader & URLClassLoader、ArrayList & LinkedList、 HashMap & LinkedHashMap & TreeMap & CouncurrentHashMap、HashSet & LinkedHashSet & TreeSet
Various variable types in Java
Familiar with the use of Java String, familiar with the various functions of String
The principle and difference of substring in JDK 6 and JDK 7,
replaceFirst、replaceAll、replace区别、
String overloads of "+",
The difference between String.valueOf and Integer.toString,
immutability of strings
Automatic unpacking
Integer's caching mechanism
Familiar with various keywords in Java
Principle and usage of transient, instanceof, volatile, synchronized, final, static, const.
Collection class
The use of common collection classes
Difference between ArrayList and LinkedList and Vector
The difference between SynchronizedList and Vector
HashMap、HashTable、ConcurrentHashMap区别
Stream related usage in Java 8
The use of apache collection processing tool class
Differences and reasons for the implementation of HashMap in different versions of JDK
enumerate
Enumeration usage, enumeration and singleton, Enum class
Java IO & Java NIO, and learn to use
The difference between bio, nio and aio, the usage and principles of the three IOs, netty
Java reflection and javassist
reflection and factory pattern, java.lang.reflect.*
Java serialization
What is serialization and deserialization and why serialization
The underlying principle of serialization
Serialization and Singleton Pattern
protobuf
Why serialization is not safe
annotation
Meta-annotations, custom annotations, the use of common annotations in Java, the combination of annotations and reflection
JMS
What is Java Message Service, JMS Messaging Model
JMX
java.lang.management.*、 javax.management.*
Generics
Generics and Inheritance
type erasure
Generic KTVE
The meaning of object, etc., various usages of generics
unit test
junit, mock, mockito, in-memory database (h2)
regular expression
java.lang.util.regex.*
Commonly used Java tool library
commons.lang, commons.*... guava-libraries netty
What is API&SPI
abnormal
Exception types, handling exceptions correctly, custom exceptions
time processing
Time Zone, Season, Time API in Java
Encoding
Solve the problem of garbled characters, common coding methods
syntactic sugar
The principle of syntactic sugar in Java, the solution of syntactic sugar
Java concurrent programming
What is a thread and the difference from a process
Read the source code and learn to use
Thread、Runnable、Callable、ReentrantLock、ReentrantReadWriteLock、Atomic*、Semaphore、CountDownLatch、、ConcurrentHashMap、Executors
Thread Pool
Design your own thread pool, submit() and execute()
thread safety
Deadlock, how to troubleshoot deadlock, Java thread scheduling, the relationship between thread safety and memory model
Lock
CAS, optimistic locks and pessimistic locks, database-related lock mechanisms, distributed locks, biased locks, lightweight locks, heavyweight locks, monitor, lock optimization, lock elimination, lock coarsening, spin locks, reentrant locks, blocking lock, deadlock
deadlock
volatile
happens-before, compiler instruction reordering, and CPU instruction reordering
synchronized
How is synchronized implemented?
The relationship between synchronized and lock
How to implement a thread-safe singleton without using synchronized
sleep 和 wait
wait 和 notify
notify 和 notifyAll
ThreadLocal
Write a deadlocked program
Write code to solve the producer consumer problem
Daemon thread
The difference and usage of daemon threads and non-daemon threads
2. Advanced Java Basic Knowledge
Bytecode, class file format
CPU cache, L1, L2, L3 and false sharing
tail recursion
bit operation
Add, Subtract, Multiply, Divide, and Take the remainder using bitwise operations
Design Patterns
Learn about 23 design patterns
Use common design patterns
Singletons, policies, factories, adapters, chains of responsibility.
Implement AOP
Implementing IOCs
Implement thread-safe singleton pattern without synchronized and lock
nio and reactor design patterns
network programming
Common protocols such as tcp, udp, http, https
Three-way handshake and four-time close, flow control and congestion control, OSI seven-layer model, tcp sticking and unpacking
Difference before http/1.0 http/1.1 http/2
Java RMI，Socket，HttpClient
cookie 与 session
cookie is disabled, how to implement session
Write a simple HTTP server for static files in Java
Implement client-side caching function, support returning 304 Implement concurrent download of a file Use thread pools to process client requests Use nio to process client requests Support simple rewrite rules The above functions need to meet the "open and closed principle" when implemented
Understand the characteristics of nginx and apache servers and build a corresponding server
Implementing FTP and SMTP Protocols with Java
way of communication between processes
What is a CDN? If realized?
What is DNS?
reverse proxy
Framework knowledge
Servlet thread safety issues
Servlet中的filter和listener
Hibernate的缓存机制
Hiberate的懒加载
Spring Bean的初始化
Spring的AOP原理
自己实现Spring的IOC
Spring MVC
Spring Boot2.0
Spring Boot的starter原理，自己实现一个starter
Spring Security
应用服务器
JBoss
tomcat
jetty
Weblogic
工具
git & svn
maven & gradle
三、 高级篇新技术
Java 8
lambda表达式、Stream API、
Java 9
Jigsaw、Jshell、Reactive Streams
Java 10
局部变量类型推断、G1的并行Full GC、ThreadLocal握手机制
Spring 5
响应式编程
Spring Boot 2.0
性能优化
使用单例、使用Future模式、使用线程池、选择就绪、减少上下文切换、减少锁粒度、数据压缩、结果缓存
线上问题分析
dump获取
线程Dump、内存Dump、gc情况
dump分析
分析死锁、分析内存泄露
自己编写各种outofmemory，stackoverflow程序
HeapOutOfMemory、 Young OutOfMemory、MethodArea OutOfMemory、ConstantPool OutOfMemory、DirectMemory OutOfMemory、Stack OutOfMemory Stack OverFlow
常见问题解决思路
内存溢出、线程死锁、类加载冲突
使用工具尝试解决以下问题，并写下总结
当一个Java程序响应很慢时如何查找问题、
当一个Java程序频繁FullGC时如何解决问题、
如何查看垃圾回收日志、
当一个Java应用发生OutOfMemory时该如何解决、
如何判断是否出现死锁、
如何判断是否存在内存泄露
编译原理知识
编译与反编译
Java代码的编译与反编译
Java的反编译工具
词法分析，语法分析（LL算法，递归下降算法，LR算法），语义分析，运行时环境，中间代码，代码生成，代码优化
操作系统知识
Linux的常用命令
进程同步
缓冲区溢出
分段和分页
虚拟内存与主存
数据库知识
MySql 执行引擎
MySQL 执行计划
如何查看执行计划，如何根据执行计划进行SQL优化
SQL优化
事务
事务的隔离级别、事务能不能实现锁的功能
数据库锁
行锁、表锁、使用数据库锁实现乐观锁、
数据库主备搭建
binlog
内存数据库
h2
常用的nosql数据库
redis、memcached
分别使用数据库锁、NoSql实现分布式锁
性能调优
数据结构与算法知识
简单的数据结构
栈、队列、链表、数组、哈希表、
树
二叉树、字典树、平衡树、排序树、B树、B+树、R树、多路树、红黑树
排序算法
各种排序算法和时间复杂度 深度优先和广度优先搜索 全排列、贪心算法、KMP算法、hash算法、海量数据处理
大数据知识
Zookeeper
基本概念、常见用法
Solr，Lucene，ElasticSearch
在linux上部署solr，solrcloud，，新增、删除、查询索引
Storm，流式计算，了解Spark，S4
在linux上部署storm，用zookeeper做协调，运行storm hello world，local和remote模式运行调试storm topology。
Hadoop，离线计算
HDFS、MapReduce
分布式日志收集flume，kafka，logstash
数据挖掘，mahout
网络安全知识
什么是XSS
XSS的防御
什么是CSRF
什么是注入攻击
SQL注入、XML注入、CRLF注入
什么是文件上传漏洞
加密与解密
MD5，SHA1、DES、AES、RSA、DSA
什么是DOS攻击和DDOS攻击
memcached为什么可以导致DDos攻击、什么是反射型DDoS
SSL、TLS，HTTPS
如何通过Hash碰撞进行DOS攻击
用openssl签一个证书部署到apache或nginx
四、架构篇分布式
数据一致性、服务治理、服务降级
分布式事务
2PC、3PC、CAP、BASE、 可靠消息最终一致性、最大努力通知、TCC
Dubbo
服务注册、服务发现，服务治理
分布式数据库
怎样打造一个分布式数据库、什么时候需要分布式数据库、mycat、otter、HBase
分布式文件系统
mfs、fastdfs
分布式缓存
缓存一致性、缓存命中率、缓存冗余
微服务
SOA、康威定律
ServiceMesh
Docker & Kubernets
Spring Boot
Spring Cloud
高并发
分库分表
CDN技术
消息队列
ActiveMQ
监控
监控什么
CPU、内存、磁盘I/O、网络I/O等
监控手段
进程监控、语义监控、机器资源监控、数据波动
监控数据采集
日志、埋点
Dapper
负载均衡
tomcat负载均衡、Nginx负载均衡
DNS
DNS原理、DNS的设计
CDN
数据一致性
五、 扩展篇云计算
IaaS、SaaS、PaaS、虚拟化技术、openstack、Serverlsess
搜索引擎
Solr、Lucene、Nutch、Elasticsearch
权限管理
Shiro
区块链
哈希算法、Merkle树、公钥密码算法、共识算法、Raft协议、Paxos 算法与 Raft 算法、拜占庭问题与算法、消息认证码与数字签名
比特币
挖矿、共识机制、闪电网络、侧链、热点问题、分叉
以太坊
超级账本
人工智能
数学基础、机器学习、人工神经网络、深度学习、应用场景。
常用框架
TensorFlow、DeepLearning4J
其他语言
Groovy、Python、Go、NodeJs、Swift、Rust
六、 推荐书籍
《深入理解Java虚拟机》
《Effective Java》
《深入分析Java Web技术内幕》
《大型网站技术架构》
《代码整洁之道》
《Head First设计模式》
《maven实战》
《区块链原理、设计与应用》
《Java并发编程实战》
《鸟哥的Linux私房菜》
《从Paxos到Zookeeper》
《架构即未来》