You can not go out at home idle years after the fart? Tencent Kong 169 Java interview questions, 40K salary offer is not a dream!

First, the basic data structures and algorithms

1. · Talk about the complexity of several common sorting algorithm and respectively.
2. · Use Java to write a bubble sort algorithm
3. · Describe the chain storage structure.
4. · How to traverse a binary tree?
5. · Inverted a LinkedList.
6. · Use Java to write a recursive directory traversal of all files.

Two, Java foundation

1. · The difference between interfaces and abstract classes?
2. · Java exception in which of these categories? Respectively, how to use?
3. · What are commonly used collection classes? Such as how to sort the List?
4. · ArrayList and LinkedList internal implementation is roughly what? The difference between them and the advantages and disadvantages?
5. • Memory overflow is how is it? Please give an example?
6. * == and equals the difference?
7. · The role of the hashCode method?
8. · NIO What is that? What applies to the scene?
9. · HashMap implementation principle, how to ensure the HashMap thread-safe?
10. · JVM memory structures, Why GC?
11. · NIO difference model, select / epoll, the multiplexing principle
12. · Java accounts for the number of characters in a byte, extended ask int, long, double-byte account number
13. • Create an instance of the class has what way?
14. · Final / finally / finalize the difference?
15. · Session / Cookie difference?
16. Difference · String / StringBuffer / StringBuilder, expanding ask their realization?
17. · Servlet life cycle?
18. · How to allocate a contiguous Java 1G memory space? What needs attention?
19. · Java has its own memory recovery mechanism, but why there are problems memory leak it?
20. · What is java serialization, how to achieve java serialization? (Write a instance)?
21. · String s = new String ( "abc"); created several String Object?

Three, JVM

1. · The basic structure of the JVM heap.
2. · JVM garbage algorithm, which has several? CMS basic flow of garbage collection?
3. · JVM What are common startup parameters can be adjusted to describe a few?
4. · How to view memory usage of the JVM?
5. · Java program is run out of memory, a memory leak occurs? A few examples.
6. · Your favorite JVM configuration and tuning parameters are what? What role are?
7. · JVM memory structures?
8. · Commonly used GC strategy, when it will trigger YGC, when triggered FGC?

Fourth, multi-threading / concurrency

1. · How to create a thread? How to ensure thread safety?
2. · How to implement a thread-safe data structure
3. · How to avoid deadlocks
4. · The role of Volatile keyword?
5. · HashMap in a multithreaded environment needs attention? why?
6. · Java program, start a thread is run or start?
7. * What is a daemon thread? What is the use?
8. · What is a deadlock? How to avoid
9. · What is the difference threads and processes are?
10. · Java inside Threadlocal is how to achieve?
11. The principle · ConcurrentHashMap is?
12. · Sleep and wait difference
13. · Notify and notifyAll difference
14. Make · volatile keyword
15. The role and realize · ThreadLocal
16. · How to execute two threads serial
17. · What is the meaning of context switches
18. • You can kill a thread running off it?
19. · What is the condition of the lock, write lock, spin locks, reentrant lock?
20. · The principle of ThreadPoolExecutor thread pool?

Five, Linux use to troubleshoot and problem analysis

1. • Create a file using two command?
2. · The difference between a hard link and soft link?
3. · Linux common commands what?
4. · Look at how resource consumption of a Java thread?
5. · Load too high possibility of What?
6. · / Etc / hosts file what to do with?
7. · How quickly will a text in all the "abc" is replaced with "xyz"?
8. · How to search in the log file to find the error log?
9. · Find enough disk space, how to quickly identify the largest files take up space?
10. · Java server troubleshooting (OOM, high CPU, High Load, class conflict)
11. · Java troubleshooter and common usage (top, iostat, vmstat, sar, tcpdump, jvisualvm, jmap, jconsole)
12. · Thread dump file how to analyze (Runnable, lock, code stack, operating system thread ID associated)
13. · How to view the thread information Java applications?

Sixth, the framework uses

1. · Describe the three Hibernate state?
2. · Spring Bean in the life cycle.
3. · SpringMVC or Struts request processing workflow.
4. · Spring AOP to solve the problem? How to achieve?
5. · Spring transaction propagation properties is how is it? What will it affect?
6. · Spring BeanFactory and in FactoryBean What is the difference?
7. · Spring IOC framework of what is the principle?
8. · Spring dependency injection, which has several ways
9. · Struts workflow
10. · How to implement a section with a Spring?
11. · Spring how to implement database transaction?
12. · Hibernate use of the twelve cache, Lazy-Load understanding;
13. · Mybatis how to submit the batch?

Seven, database-related

1. · MySQL InnoDB, Mysaim features?
2. · Optimistic and pessimistic locking difference?
3. · What database isolation level? what's the effect?
4. · MySQL master the basic principles of synchronization equipment.
5. · Select * from table> sql statement 10 group by size order by size order of execution t where size?
6. · How to optimize database performance (index, sub-library sub-table, bulk operations, paging algorithm, upgrade the hard disk SSD, business optimization, master-slave deployment)
7. · Under what circumstances do not use SQL index (not included, not equal to, function)
8. · In what field general construction index (up to filter data fields)
9. · How to find out from a table name field does not contain "XYZ" of all lines?
10. · MySQL, B + index to achieve, achieve row lock, SQL optimization
11. · Redis, RDB and AOF, how do high availability, clustering
12. · How to address the high concurrency reduce inventory problems
13. · Implementation mechanism in the index mysql storage engines;
14. · Several database size matters;
15. · Row locks, table locks; optimistic locking, pessimistic locking

Eight, network protocols and network programming

1. · TCP connection establishment.
2. · TCP connection disconnected process.
3. 302 jump logic behind-browser happen?
4. · HTTP protocol interaction process. Differences HTTP and HTTPS, SSL interactive process?
5. · Rest and Http What is the relationship? Everyone says Rest is very lightweight, and how your understanding of Rest style?
6. · TCP sliding window protocol what's the use? Talk about the principle.
7. · HTTP protocol has what method?
8. · The difference between switches and routers?
9. · The basic flow Socket interaction?
10. · Protocol (message structure, HTTP, multi-threaded download, what is the long connection)
11. · Tcp protocol (even build process, slow start, sliding window, seven-layer model)
12. · Webservice protocol (wsdl / soap format, the difference between the agreement and the rest)
13. · NIO advantage of, Netty threading model, what is the zero-copy

Nine, Redis and other caching systems / middleware / NoSQL / consistency Hash, etc.

1. · A common list of Redis client concurrency model.
2. · HBase how to implement fuzzy query?
3. · A list of commonly used messaging middleware, if the message you want to order preserving how to achieve?
4. · How to achieve a Hashtable? How do you design considerations Hash conflict? How to optimize?
5. · Distributed cache coherence hash
6. · LRU algorithm, slab allocation, how to reduce memory fragmentation
7. · How to solve the stand-alone cache hot issues
8. · What is the Bloom filter, which implements the principle is? False positive refers?
9. · The difference memcache and redis
10. · Zookeeper on how what features election algorithm
11. · Map / reduce process, how the two data sources with map / reduce joint statistics

Ten, design patterns and Reconstruction

1. · You can, for example several common design patterns
2. · What would you follow the principle in the design of a plant when the package?
3. · You can use a list of Visitor / Decorator pattern of open source projects / libraries do?
4. · What are your most commonly used in the coding of design patterns? Under what scenario with?
5. · How to implement a singleton?
6. • Proxy mode (Dynamic Proxy)
7. · Singleton (lazy mode, villains mode, how to solve the concurrent initialization, volatile and lock usage)
8. · JDK source inside are what impressed you use design patterns, for example to see?

XI: Micro Service

1. What is micro-services?

2, between the micro-communication service is how independent

3, springCloud and dubbo What are the differences?

4, springboot and springcloud, you talk about their understanding?

5. What is the micro-blown service? What is service degradation?

6, advantages and disadvantages of micro What are the services? Under said pit you encountered in project development

7, you know what micro-services technology stack? Please name a few

8, eureka and zookeeper can provide functionality registration and discovery services, please talk about the difference between the two?

I believe you may have experienced these:

Have been working for two or three years, each project will go all out to complete work overtime, wage growth is not satisfactory.

After leaving I heard years old colleagues, he won just quit paying offer, 500,000 annual salary went straight up.

Now that the company out of the reach of new technologies, their market competitiveness tremendous anxiety, how to get future career path?

The cold winter, you finally understand that now very few job opportunities, salary is difficult to have a larger increase, salary engineer Java skills are determined, it's time to improve your skills, plan your future career path up.

As your Java engineers usually work has been very busy, in the end how advanced, can quickly grow up?

Share some experience of someone who, for your reference.

Once they become a Java engineer, it is destined to lifelong learning.

13 years of Java engineer career, this is fully understood, and let me insist on motivation to learn, mainly from the following three aspects:

1, continue to add value themselves, have more options

If the technical likened to a tree, each learn a language, then lit a fruit tree, you will, the more technology and more fruit trees, the greater the value. When the fruit of the tree of technology accumulated to a certain extent, you can go higher order longitudinal direction of technology promotion, career development path to the next level.

2, the Internet is no comfort zone, is stalled regress

Computer technology updates fast iteration, new technologies emerging, if you want to become a good Java engineers, we must be ready at any time to learn, and perseverance, so as to keep up with the rapid pace of development of Internet.

3, learning is the best way to face competition, through a midlife crisis

Java engineers are well-paid profession, under the rapid development of the Internet in recent years, but became a sought-after hot career that plunge into this career more and more people, mighty force in single, do not want to fall behind, only study hard and become a paying Internet companies compete for the high-end Java engineers to fear winter.

Currently Internet winter so many people awake Internet, many large enterprises layoffs, hiring demand contraction, mainly for foundation posts, warm boiled frog to cook that wave of people dead, high-end Java engineers in the market is still in short supply.

Internet companies mainstream technology selection

Advanced Senior Java, architects will learn six key skills, including: data structures and algorithms, Java advanced features, source code analysis, database, Java framework with the necessary tools, system architecture design, hoping to really want to help from advanced programmers for advanced Java, architect of the road friends.

1, concurrent programming

Through in-depth understanding of the operation principle of the lowest level, strengthen logical thinking in order to write efficient, secure multi-threaded programs.

Comprising: a frame set (source), tools, frame Spring, SpringMVC, Mybatis, Shiro, Netty, the server (tomcat, Nginx), network programming, serialization, the JVM and the like.

 

 

2, design patterns

Design patterns are Reusable Object-Oriented Software, learning design mode test every Java is the only way to engineer advanced, flexible use of design patterns, you can make the code becomes simple, easy to understand, reuse more high.

Common commonly used design patterns are: the factory mode, proxy mode.

 

3, R & D framework related tools

For Java programmers, below these frameworks and tools is often used. 工欲善其事必先利其器, master and apply these tools to help us more efficiently, work quality, for example, debug, efficient de-duplication, the code review and so on.

 

3, distributed architecture

With the increasing importance of the traffic volume and body, we can not correspond to a large single structure model application scenario, the system would never allow the overall result in single point of failure is unavailable, only a vertical or horizontal split service system, a distributed form architecture to eliminate single points of failure, thereby increasing overall system availability.

Comprising: the Session distributed, distributed cache, a database, consistency, load balancing, message queue (RabbitMQ, ZeroMQ, Kafka), etc.

 

4, micro-services

When the result of local conditions, choose to use the service gains micro-architecture will far outweigh the costs.

Small-scale enterprises can be considered appropriate to introduce an appropriate micro-service architecture, the transformation of existing systems or new micro-services application, the gradual accumulation of micro-services architecture experience, not to the overall implementation of micro-service architecture, comprehensive consideration of cost and efficiency, practicality.

Mike released in to the period architecture series "BAT architecture technology topics collection", there are series of articles for the micro-services, the end the ability to view the address.

 

5, JVM performance optimization

 

6, critical infrastructure architecture

 

Finally I want to say that, in the workplace or, life worth mentioning, each stage has some obstacles and bottlenecks, which we have experienced.

If you are able to recognize their own as well as the stage, targeted to think, charging, doing the right thing, pay more effort than others, you will be more outstanding than others, have more opportunities, this is what we often say that the Matthew effect: the more work, the more luck.

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Having said that, in the end how to learn it, there is no data or video ah?

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