Lagou Java Employment Training Camp

Basic questions
Language
talk about your understanding of the Java language;
whether you have been in contact with other development languages, talk about the advantages, disadvantages or differences between the Java language and other languages;
Features
Explain your understanding of the three major features of the Java language;
combined with the project, say Say your use and understanding of the three major features;
how do you view the abuse of the three major features in Java, or the difference between minimalist code and redundant code, which one
you prefer; if you are asked to design a functional module, you will learn from Which aspects are considered;
whether a class can be multiple inherited or multiple implementations;
the difference between interface classes and abstract classes;
design patterns
commonly used in Java ; design patterns used in
projects ; design patterns used in the
Spring framework, enumerate a few A; basic
types in
Java;
talk about the understanding of String;
if you are asked to redefine a String class, talk about the implementation;
several ways to create variables:
comparison of basic types,'==' and'equals' Difference; the difference between
String, StringBuilder and StringBuffer;
/**

• The value of the integer literal is between -128 and 127, then the new Integer object will not be new, but the Integer object in the constant pool will be directly referenced, so f1The result of f2 is true, and f3The result of f4 is false.
  */
  @Test
  public void compareTest() { Integer num1 = 100, num2 = 100, num3 = 150, num4 = 150; System.out.println(num1 == num2); // true System. out.println(num3 == num4); // false } Serialization Talk about your understanding of serialization; talk about the scenarios in which serialization is used in the project; when a class implements serialization, there will be a serialVersionUID, talk about it The role of multithreading ; talk about the understanding of Java multithreading; talk about the multithreading used in your project; how to ensure thread safety; briefly describe ThreadLocal; whether the Bean instance in the service is single-threaded or multi-threaded; the underlying implementation of Redis is Single-threaded or multi-threaded; talk about the understanding of thread pools; sorting Briefly describe several sorting algorithms and corresponding complexity; bubble sorting; quick sorting, when to reach the maximum complexity; heap sorting; insertion sorting; collection ArrayLIst Different from LInkList;
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  The realization principle of
  ArrayList and LinkList; whether ArrayList and LInkList are thread-safe;
  the optimal usage scenarios of ArrayList and LinkList;
  whether you have understood the jdk source code, briefly describe several implementation classes of Map;
  talk about the understanding of HashMap; the
  underlying HashMap Storage structure;
  The difference between
  HashTable and HashMap; Is thread safe in HashTable and HashMap; Whether
  JVM
  objects are created in the heap or the stack;
  Briefly describe the GC process;
  Briefly describe the new and old generations;
  each area in the new generation The role of the
  method ; the invocation process of the method in the stack;
  advanced questions
  frame
  talk about the understanding of
  SpringMVC; the difference between SpringBoot and SpringMVC;
  talk about the understanding of SpringBoot (pros and cons);
  talk about your understanding of the Dubbo framework;
  The difference between Rpc call and Http call;
  What protocol is used to call
  Dubbo service ; The call method of Dubbo service
  ;
  Zookeeper function; Zookeepper is down, whether the dubbo service can be called normally;
  whether dubbo has been extended during project development Development;
  Briefly describe AOP and IOC in Spring;
  Do you understand SpringCloud;
  zookeeper realizes the principle of distributed locks; what are the types of data stored in
  Redis
  redis;
  tells about the realization principle of zSet sorting in
  redis ; how to use redis to realize distributed locks;
  what problems will there be when redis is used for distributed locks , How to solve it;
  the storage structure of data in
  redis ; is the bottom layer of redis single-threaded or multi-threaded; where
  is the performance bottleneck of redis;
  briefly describe the principle of I/O multiplexing;
  briefly describe the consistent Hash or hash ring;