Most complete history of Java engineers face questions summary, monthly plenary session at least 3W

To facilitate the review after the interview the students, I put all kinds of questions to an aggregate face a moment after each question are themselves feel the need to master the screening, the finishing including Java, data structures and algorithms, computer networks, operating systems , databases and so on. Later I will answer these questions one after another put out.

Java Basics

• Java difference in the == and equals and hashCode
• The difference between int and integer
• Meaning abstract class
• The difference between abstract classes and interfaces
• Can I create an immutable object that contains a variable object?
• Talk about the understanding of java polymorphism
• String、StringBuffer、StringBuilder区别
• Generics in the difference between extends and super
• The difference between processes and threads
• The difference between final, finally, finalize the
• Serialization way
• Convert string to integer manner and principle
• Whether static properties and static methods can be inherited? It can be rewritten? And why?
• Members of the inner class, understanding the static inner classes, local inner classes and anonymous inner classes, as well as project application
• Talk about common coding?
• How to format date?
• Java's exception system
• What is unusual chain
• The difference between the throw and throws
• Principles of reflection, reflecting what three ways to create a class instance yes.
• Among the four kinds of java references
• What deep copy and shallow copy difference is?
• What is the compiler constants? What are the risks of using it?
• You intern String object () be familiar with it?
• a = a + b and a + = b Is there any difference?
• The difference between static and dynamic proxy agent, what the scene to use?
• What is the mechanism implemented in Java polymorphism is?
• How a Java object serialization to a file?
• Talk about your understanding of Java reflection
• Talk about your understanding of Java annotations
• Talk about your understanding of dependency injection
• Say something generic principles and examples
• Java in String understanding
• Why String designed to be immutable?
• equal and hashCode methods of the Object class rewrite, and why?

Multithreading

• Three ways to turn thread?
• The difference between talk about processes, threads, coroutines
• How to communicate between threads?
• What is Daemon thread? What does it mean?
• Daemon thread local differences and thread in java?
• Why should there be a thread, rather than the single process?
• What is reentrant lock (ReentrantLock)?
• What is the thread group, why not recommended in Java?
• Optimistic and pessimistic locking and understanding of how to achieve, what are the implementation?
• What thread scheduling algorithm is used in Java?
• Synchronization method and synchronized block, which is the better choice?
• run () and start () method distinction
• How to control a method allows concurrent access to the number of threads?
• Different in Java and wait seelp methods;
• yield method of the Thread class in what role?
• What is immutable, it has to write concurrent applications going to help?
• Talk to wait
• Understanding tify keyword
• Why wait, notify and notifyAll these methods are not thread inside the class?
• What causes threads blocked?
• Talk about the method of synchronization in java
• Talk to Synchronized keyword, class locks, lock method, reentrant lock understanding
• Multi-thread access and the role of static synchronized method
• The same class which two synchronized method, the problem of two threads access
• How do you make sure that the thread main () method where the Java program is the final end of the thread?
• To talk about the role of the volatile keyword
• To talk about the role of ThreadLocal keywords
• Talk about understanding the NIO
• What are Callable and Future?
• Difference ThreadLocal, synchronized and volatile keywords
• The difference between synchronized and Lock
• ReentrantLock, synchronized and volatile Compare
• What is the difference in Java CycliBarriar and CountdownLatch?
• CopyOnWriteArrayList can be used in what scenario?
• ReentrantLock internal implementation
• lock principle
• What Semaphore in Java that?
• InvokeAndWait in Java and invokeLater What is the difference?
• What are you doing multi-threading cycle is?
• How to detect whether a thread has a lock?
• The four necessary conditions for deadlock?
• Whether the object class lock and the lock will affect each other?
• What is the thread pool, how to use?
• Java threads in the pool submit () and execute () method What is the difference?
• Differences in Java interrupted and isInterruptedd methods?
• Achieve blocking queue in Java
• BlockingQueue description:
• Multithreading have any questions to pay attention?
• How to ensure the safety of multi-threaded file read and write?
• Multi-threaded HTTP principle
• Realization of HTTP
• Achieve producer-consumer model
• What in Java ReadWriteLock that?
• Written in Java will lead to a deadlock in the program, you will be how to solve?
• SimpleDateFormat is thread safe?
• Synchronized set of concurrent collections in Java What is the difference?
• What degree of concurrency in Java ConcurrentHashMap is?
• What is Java Timer class? How to create a task specific time interval?

set

• Collection and Collections of the difference?
• A modification of the object equals method signature, then use a HashMap to store the object instance when the equals method which will call?
• The difference between List, Set, Map of
• List and Map implementations and storage
• The principle of HashMap
• How HashMap put data (from HashMap to explain the source point of view)?
• HashMap expansion operation is how to achieve?
• What are the different HashMap in JDK1.7 and JDK1.8 in?
• The principle of ConcurrentHashMap
• The principle HashTable
• Comparison of ArrayMap and HashMap
• The difference between HashMap and HashTable
• The difference between HashMap and HashSet
• Hash collection Set realize how to prevent collisions
• The difference between arrays and linked lists
• What is the difference between Array and ArrayList? When more suitable Array
• What .EnumSet that?
• What is the difference Comparable and Comparator interfaces?
• Quick failure mechanism Java collections of "fail-fast"?
• The difference between the fail-fast and fail-safe?
• What BlockingQueue that?
• What is the role Iterator class
• poll () method and remove () method difference?
• Why JAVA8 of ConcurrentHashMap abandoned segmented lock, there is a problem, and if you come to design, how do you set up

JVM

• It will trigger initialization class under what circumstances?
• Talk about your understanding of the analysis and dispatched.
• You know what, or what your line Using GC policy? Is there any advantage, is useful when what scene?
• Ja0v00a class loader package includes 00 species to get accustomed 0? ⽗ submenus that the relationship between them is how? Parents delegate mechanisms mean? what is the benefit?
• How Custom ⼀ a class loader? Use what you had or you need ⼀ a Custom under what scenario class loader it?
• What parameters are set heap memory?
• Perm Space saved what data? Cause OutOfMemory it?
• In doing GC, in what order ⼀ objects to be moved in various Space memory is?
• Have you ever encountered OutOfMemory problem? You are how to deal with this problem? What have you learned in the process there?
• StackOverflow anomalies have never met before? Shoots as usual you guess will be triggered under what circumstances? How to specify the stack zoomed ⼩ ⼀ threads? How many shoots as usual you write?
• Memory model and a partition, you need to detail what to put in each area.
• Denomination: Static and dynamic assignment assignment.
• What optimization strategy at runtime virtual machine
• Please explain the difference between StackOverflowError and OutOfMemeryError of?
• In the JVM, how to determine whether an object death?

computer network

• 10M load a picture from the network, said Caution
• OSI network architecture and TCP / IP protocol model
• TCP three-way handshake and four wave
• Why TCP connection requires three-way handshake, the two can not be what, and why?
• How TCP protocols to ensure the reliability of transmission
• The difference between TCP and UDP
• What are the TCP and UDP applications
• HTTP1.0 and 2.0 difference
• HTTP packet structure
• HTTP connections long and short connection?
• The difference between HTTP and HTTPS and how to implement security
• How to verify the legitimacy of the certificate
• Get the difference and the POST
• TCP's congestion handling
• How TCP flow control
• TCP and UDP respectively corresponding to the common application layer protocol
• Classification of IP addresses
• With only Mac also need to address why IP address?
• Switches, hubs and routers What is the difference?
• The role of bridge
• ARP ARP is a simple language to explain how it works.
• Network Interface Card (NIC) functionality?
• IO in synchronous and asynchronous, non-blocking and blocking difference
• The difference between URI and URL
• Meaning in URL-encoded GET request
• Common status code and reason phrase
• Talk about Session, Cookie and Application
• How to avoid browser cache
• What is a block transfer.
• SQL injection talk
• DDos attack
• DDos attack prevention methods are those?
• What is XSS attack
• The process of obtaining input from a URL to a page
• Data Structures and Algorithms
• This part of the manual to be realized some of the data structure, I summed up the following important data structures

data structure

• List (operation check deletions) singly linked list doubly linked list
• Queue (operation check deletions) Normal priority queue teammate
• Binary Tree (preamble, in sequence, after) balanced tree (as far as possible will be achieved code) stack red-black tree (understanding of the nature, application scenarios) B tree (understanding of the nature, application scenarios)
• Figure depth-first search breadth-first search algorithm shortest path Prim Kruskal minimum spanning tree algorithm
• Topology
• String algorithm Knuth-Morris-Pratt algorithm Boyer-Moore
• Hash

Several algorithms thought

• Recursion
• Recurrence
• greedy
• enumerate
• Dynamic Programming
• Backtracking
• Divide and Conquer

We will learn the top ten ranking algorithm

• Selection Sort
• Insertion Sort
• Bubble Sort
• Shell sort
• Merge sort
• Quick Sort
• Heapsort
• Counting Sort
• Bucket sort
• Radix Sort

database

• Please concise description of four kinds of transaction isolation level in InnoDB Mysql name support, as well as the distinction between progressive?
• What's in Mysql ENUM in use is?
• CHAR and VARCHAR difference is?
• How transactions are implemented through the log, the better the more he says
• Difference drop, delete and truncate the
• The principle of locality and disk read-ahead
• Database paradigm
• The difference between stored procedures and triggers
• Lock optimization strategy
• Set up under what circumstances the index but can not be used
• Under what circumstances should not be indexed?
• MySQL connection outer explained, the difference between self-connected connector
• Integrity constraints, including what?
• Mysql storage engine, the difference myisam and innodb.
• How to optimize SQL
• What optimistic and pessimistic locking lock is, INNODB standard row-level locking which of two kinds, to explain its meaning.
• MVCC meaning, how to achieve
• MYSQL master how to solve the delay.

spring

1. spring Overview

• What are the benefits of using Spring framework is?
• Which modules of Spring?
• AOP module explanation
• WEB module explanation
• Core container (application context) module.
• What is the Spring IOC container?
• What are the advantages IOC is?
• What usually ApplicationContext implementation is?
• Bean plants and Application contexts What is the difference?
• Bean plants and Application contexts What is the difference?

2. spring dependency injection

• What is Spring's dependency injection?
• What are the different types of IOC have (dependency injection) way?
• What is Spring beans?
• What a Spring Bean definition contains?
• Scope explain Spring supports several bean.
• Singleton bean Spring Framework is thread safe?
• Explain Spring Framework bean life cycle
• What is important bean life cycle approach? You can reload them?
• What is bean assembly?
• What is the bean automatic assembly?
• Automatic assembly interpreted in different ways.
• What are the limitations of automatic assembly have?

3. spring notes

• How to Open comments assembly?
• Talk @Required, @Autowired, @Qualifier comment.

4, spring data access

• How to more effectively use the Spring JDBC framework?
• Access Hibernate by what means to use Spring?
• Transaction management Spring Framework What are the advantages?

5. Spring Aspect Oriented Programming (AOP)

• Explain AOPAspect section in Spring AOP, the difference concerns and crosscutting concerns what?
• There are several different types of notification automatic proxy?
• What is weaving. What is the difference woven into the application?

6. springMVC

• What is Spring MVC framework?
• DispatcherServletWebApplicationContext What is the controller of Spring MVC framework? @Controller comment @RequestMapping comment

JavaWeb

servlet与Tomcat

• Servlet life cycle of the difference between forward and redirect
• How tomcat servlet container class instance is created?
• What principle is used? What is a cookie?
• Session cookie and what is the difference?
• Servlet security issues
• Tomcat Connector, which has several operating modes (optimized)?

JSP

• jsp contains static and dynamic differences included
• Which jsp built-in objects they have? What role are?
• The difference between jsp and servlet, the common, the scope of their application?
• Write five kinds of commonly used JSTL tag
• JSP is how it is executed? The efficiency is lower than SERVLET it?
• Tell the difference between Servlet and CGI?
• Brief design pattern of JSP.

At last

Behind will continue to find some other, for example redis, message queues, and a number of scenario-based questions, being the first to put so much behind will continue to answer them.

Finally, the light to face questions not give you the answer has been sorted out

I welcome you to come to acquire,

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