Java Background face test __java

Java Background development face test

Java basic JVM related JUC concurrency related Spring distributed correlation algorithm data structure design pattern database Redis cache related network related other

Java Basics

Arrays.sort realization principle and collection realization principle
The difference between a foreach and a while (after compilation)
Types of thread pools, differences and usage scenarios
Analysis of the implementation principle of thread pool and the scheduling process of threads
How the thread pool is tuned
Maximum number of threads for thread pool based on what determines
Several ways of dynamic proxy
Concurrency problems with HashMap
Understand the application of Linkedhashmap?
The principle of reflection, what are the three ways that reflection creates class instances.
Cloneable interface Implementation principle, shallow copy or deep copy
Java NiO uses
Hashtable and HashMap the difference and implementation principle, HashMap will ask the array index, hash collision how to solve
Difference between ArrayList and LinkedList and its realization principle
In reflection, the difference between Class.forName and ClassLoader
The difference between the String,stringbuffer,stringbuilder.
Is there any possibility that 2 unequal objects have the same hashcode
Describe the best practices of NIO, such as Netty,mina
The implementation principle of TreeMap JVM related

The instantiation order of the class, such as parent static data, constructors, fields, subclass static data, constructors, fields, their execution order
JVM memory,
Java 8 memory generational improvement
JVM garbage collection mechanism, when triggers minorgc, and so on
What is a complete GC process (from YGC to FGC) in the JVM, focusing on how the object is promoted to the old age, several major JVM parameters, etc.
you know what kinds of garbage collectors, their pros and cons, focus on the next CMS,G1
New generation and generations of memory recycling policies
Eden and survivor proportional allocation, etc.
in-depth analysis of classloader, parental delegation mechanism
JVM Compilation optimization
Understanding of the Java memory model, and its application in concurrency
instruction reordering, memory fence, etc.
Oom error, StackOverflow error, PermGen space error
JVM common parameters
Tomcat structure, class loader process
volatile semantics, it modifies the variable certain thread safe
G1 and CMS differences, Throughput priority and Response priority garbage collector selection
Talk about your understanding of environmental variables classpath. If a class is not under Classpath, why throw a classnotfoundexception exception, and how to load the class correctly without changing the path of the class.
say strong references, soft references, weak references, virtual references, and the relationships between them and the GC juc/concurrency related

Threadlocal used, the principle is what, use the time to pay attention to what
The difference between synchronized and lock
The principle of synchronized, what is spin lock, bias lock, lightweight lock, what is called reentrant Lock, what is called fair lock and unjust lock
Concurrenthashmap concrete realization and its principle, jdk8 under the revision
What atomic classes they used, their parameters and their principles
What the CAS is, what problems he will have (the resolution of the ABA problem, such as the number of changes added, version number)
What would you do if you were to implement a linked list of concurrent security?
A brief account of the usefulness and differences of Concurrentlinkedqueue and Linkedblockingqueue
A brief introduction to the realization principle of AQS
The use of Countdowlatch and Cyclicbarrier, and the differences between them?
What classes are used in the concurrent package. Say what scene to use separately. Why to use.
Locksupport Tools
Condition interface and its realization principle
Understanding of the Fork/join framework
The understanding of Jdk8 's Parallelstream
The principle of segmental locking and the reduction of lock strength Spring

Spring AOP and the implementation principle of IOC
The difference between spring's beanfactory and Factorybean
Why the Cglib method can implement proxies for interfaces.
RMI and proxy mode
The transaction isolation level of spring, the principle of implementation
The understanding of spring, not the principle of single injection. It's life cycle. The principle of cyclic injection, the implementation principle of AOP, say some of the terms in AOP, how they work with each other.
The principle of the bottom implementation of MyBatis
MVC framework principle, they are all how to do URL routing
Spring boot features, advantages, applicable scenarios, etc.
Quartz and timer contrast
Spring's controller is a single case or multiple cases, how to guarantee concurrent security distributed correlation

The principle and mechanism of Dubbo implementation
Describes the detailed process of a service from publishing to being consumed
How to do service governance in distributed system
The concept of power of an interface
How message middleware resolves message loss issues
How to handle Dubbo service request failure
Whether or not the connection mechanism will cause errors
The understanding of distributed transactions
How to achieve load balancing, which algorithms can be implemented.
The purpose of zookeeper, what is the principle of the election.
The vertical split of the data horizontally.
Zookeeper principle and applicable scene
Zookeeper Watch mechanism
How to deal with REDIS/ZK node downtime
How to make unique serial numbers under distributed cluster
How to make a distributed lock
Which MQ, how to use, and other MQ compare advantages and disadvantages, MQ connection is thread safe?
How data from MQ systems is guaranteed not to be lost
Enumerate the database sub-tables that you can think of, and then how to solve the problem of the whole table query after the divide-and-sink table. Algorithm & Data structure & design pattern

Massive URL to the problem (Prum filter)
Array and linked list data structure description, each time complexity degree
Binary Tree Traversal
Quick Sort
Btree-related operations
What design patterns have you encountered at work and how they are applied
hash algorithm of what kinds, advantages and disadvantages, use the scene
What is a consistency hash
Paxos algorithm
Between the adorner mode and the proxy mode, how do you choose, please talk with your own reality
The steps and reasons for code refactoring, if you understand refactoring to schema. Database

MySQL InnoDB Storage File structure
How the index tree is maintained.
Possible problems with database self-adding primary keys
Several optimizations of MySQL
Why is the MySQL index using a B + Tree
Related processing of database lock table
Index Expiration Scenario
High concurrency under how to do security to modify the same row of data, optimistic lock and pessimistic lock is what, InnoDB row-level lock there are 2 kinds, explain its meaning
Database deadlock, for example, how MySQL solves the deadlock redis& cache-related

Redis Concurrent competition Problem How do I solve CAS operations that understand Redis transactions?
Cache Machine Additions and deletions how to minimize the impact of the system, the implementation of a consistent hash
Several ways of Redis persistence, what are the advantages and disadvantages, how to achieve
Cache invalidation Policy for Redis
Caching-Penetration Solutions
Redis cluster, high availability, principle
MySQL has 2000w data, Redis only 20w of data, how to ensure that the data in Redis is hot data
Redis and any language to implement a malicious login protection code, limit 1 hours per User ID can only log on 5 times
Redis Data Elimination Strategy network related

What's the difference between http1.0 and http1.1?
TCP/IP protocol
TCP three handshake and four wave of the process, why disconnect to 4 times, if the handshake only two times, what will appear
The difference between time_wait and close_wait
Tell me about several HTTP response codes you know.
What does the computer do when you open a link in a browser?
How TCP/IP guarantees reliability and what data packets make up
Long connection and short connection
HTTP request get and post differences and packet format
The process of TCP establishing 3 handshake and disconnecting 4 times is briefly described, and when the connection is closed, it is caused by excessive timewait, whether it appears on the active or passive disconnected side. other

maven resolves a dependency conflict, the difference between a snapshot version and a release
Linux under the IO model there are several, what their meaning is
Actual scenario problem, how to sort and handle SQL operations with mass login log, mainly the application of index and aggregate function
Real scene problem solving, typical top k problem
On-line bug handling process
How to discover problems from online logs
What commands does Linux use to find out where the problem is (such as IO intensive tasks, CPU excess)
Scene problem, there is a third-party interface, there are a number of threads to call to get the data, now specify a maximum of 10 threads per second to call it at the same time, how to do.
Print ABC three letters in sequential order with three threads, such as ABCABCABC.
What are the common caching strategies, what caching systems are used in your project, and how to design
Design a second kill system, 30 minutes without payment will automatically close the transaction (concurrency will be very high)
Please list the performance test tools that you know
How the backend system prevents requests from being submitted repeatedly.

Turn from: http://blog.csdn.net/u011001723/article/details/53457190