Java Foundation-java Core Knowledge Base

1, SPRING.MVC advantages, principles, processes

2, the principle advantage of MyBatis
3. The principle of the objects in the collection
4, the principle of expansion, especially the bottom of the map
5, Hashmap, Hashtable and cocurrenthashmap differences, to speak out their respective implementation principles, such as the Hashmap of the expansion mechanism, Cocurrenthashmap Zhi principle, multi-threaded security.
6. Several methods of thread pool making, the difference
7. What are the various states of the thread and how are they converted?
8, RPC principle, and the approximate process
9, the difference between NiO and Netty, why Netty High performance, Nio,bio,aio difference
10. The difference between blocking IO and non-blocking IO
11. Redis Cluster
12, the difference of various locks, the principle of use, and the degree of familiarity of the contract
13. Usage scenarios for Redis and database integration
14. Memached process and principle (less questions)
15, the principle of Redis to do the queue
16, ZK do the principle of subscription, the bottom, ZK election algorithm, how to deal with
17, the solution of the hash collision
18, TreeMap red black tree (ask less)
19. JVM Tuning Experience
20, JVM memory model, JVM Parental delegation, JVM common parameters, you usually tune how to set, for example.
21. Class loader mechanism
22. Database Index
23. Handwritten recursion, handwritten binary search, handwriting producer, consumer model
24, JS closed packet (less asked)
25. Does NiO know what the notification mechanism is after blocking?
26. What are the problems with serialization ID for the serialization of Java?
27. What is the difference between executor and executors in Java?
28. Why is it better to use the executor framework than to create and manage threads with apps?
29, how to use Linux command to analyze the JVM inside the thread blocked
30. What is the thread scheduling algorithm used in Java?
31. What is context switching in multi-threading?
32, ClassLoader structure, whether you can define a java.lang.String class, why? Parental agent mechanism.
33, have not done the JVM memory tuning, how to do, for example, used what tools?
34. What is the key to volatile in Java? How to use it? How does it differ from the synchronized method in Java?
35, the interviewer from the resume to draw a more interested in the project, let the project brief introduction, the project asked a few technical questions
36, introduce the garbage collection mechanism in Java, programmers usually need to pay attention to this? Why? Please illustrate.
37, the Database isolation level introduction, the example explanation.
38, the difference between override and overload.
39, to find the maximum distance of the binary tree (that is, the farthest from the two leaf nodes), write code.
40, two stacks to implement a queue, write code.
41. What do you think your advantage is? Are there any weak points of technology?
42, database SQL tuning, slow SQL location
43. What kinds of index, difference, use scene
44, MySQL engine, which kinds of, the difference between the use of the scene
45, the use of Linux shell scripts, statistics, sorting and so on
46, Linux Common commands, such as the top command to see the meaning of each parameter after the process
47. Optimistic lock and pessimistic lock
48, the configuration of Nginx
49, you encounter the oom problem, how to solve.
50, you have encountered in the project of high concurrency problems, how to solve.
51. What are the advantages and disadvantages of common load balancing strategies, and what
52, Jdk\bin under the tools you have used which

Algorithm Basics

Java is basically written to do the application system, the opportunity to use the algorithm is almost no, so generally do not exam. But if the working life is longer, discouragement interviewer doubt your programming ability, deliberately want to test, so fast platoon, heap row, reverse linked list, traverse binary tree and other basis or review it.
If the face of the bat core Department, worried about meet the people, can also review the "beauty of programming" and the like.
Algorithm problem, can not write code, but if you say the idea will be added points

Java Basics

HashMap interviewer most like to test, must understand the principle.
TreeMap know can, should no one's idle egg pain Test red black tree.
Threadlocal interviewers also like to test, to understand the principle
Reflection, dynamic Agent, IOC, AOP review, almost must test
NIO, Aio almost always ask, time to write routines, know Netty Mina
Class loader: Knowing the parental assignment, if you know Tomcat, Jetty class loader is better

Gc

GC Many interviewers like to test
Before the interview to memorize various GC algorithm differences, understanding the principle.
G1 Many interviewers themselves do not understand, there is no time to take care of.

High concurrency

Traditional it generally does not touch high concurrency, but it's okay to do as follows, the interview is not a problem to deal with
Java.util.concurrent all the following packages and classes read through, understand the principle, remember the core code, write routines, there are many concurrent related to the principle of the article, the article to see the source code to understand the problem is not very small.
Some of the code is complex, such as AQS, can not understand even, do not take too much effort, remember the principle can, because most of the interviewer also do not understand.
Be sure to write routines, routines that are best associated with your business, so that the interview is the code of your actual project.
The interviewer likes to test the following categories: Concurrenthashmap, read/write lock, Condition, thread pool, Barrier, Countdownlatch, callable, Blockingqueue

HDFs and Mr

Traditional it is generally also not contact, if you do not want to prepare it, if you want to prepare, in their own development machine took 3 Linux virtual machine, follow the online tutorial yourself step by step took a hadoop environment out, and then find a few real business generated in the log, write a few Mr Procedures to deal with.
The interview can be very modest to say that the actual project used, but not much

Application Server

WebSphere, WebLogic, JBoss and so on don't have to be prepared, nobody should ask you this.
If you have time, look at the source code of Tomcat and jetty, focusing on threading model and IO, which will be a good addition.

Database

Oracle, Sybase, DB2 no one cares, if you haven't used MySQL before, look for a book that introduces InnoDB principles and read it through.
1, understand the difference between MyISAM and InnoDB 2, understand the principle of relational database index, understand some simple index optimization principle.
The interviewer likes to give a bunch of where clauses, test indexes, compound indexes.
3. What are the scenarios that cause database indexing to fail?
4. What is the difference between not and not exists? In query does not handle NULL
5, like whether to go index? What's the situation under what circumstances do not go

Cache

Consistent hashing many interviewers like to test, prepare ahead of time.

SSH Framework

These things have not been done before, this framework-level thing, for an experienced Java code Farm, learning is a matter of minutes.
But you can also say that I did not use, but I know the principle, and then said a bunch of dynamic agents, cglib principle out, but also add points.

These are some interview topics, and basic knowledge. If at the same time in the production environment, there are a lot of troubleshooting problems in the experience, will be compared to add points. The general interview is not a problem, but still will review writing code skills, so still need to prepare under

Java Foundation-java Core Knowledge Base