Interview questions
1、 What is bytecode ? What are the advantages of bytecode ?
2、 Oracle JDK and OpenJDK Comparison of ?
3、Arrays.sort and Collections.sort Implementation principle and difference
4、wait and sleep What's the difference ?
5、 How arrays are allocated in memory ?
6、HashMap 1.7 And 1.8 Of difference , explain 1.8 What optimizations have been made , How to optimize ?
7、HashMap Expansion process
8、HashMap Is it thread safe , Why not thread safe ( It is best to draw a picture to show that multithreaded environments are not safe )?
9、HashSet How do you make sure you don't repeat ?
10、 Memory model and partition , What to put in each area in detail ?
11、 Partitions in the heap :Eden,survival (from+ to), Old age , Their characteristics are ?
12、GC What are the two methods of judging ?
13、SafePoint What is it? ?
14、GC Three collection methods of : Mark clear 、 Tag to sort out 、 Principle and characteristics of replication algorithm , Where to use them separately , If you want to optimize the collection method , What's the idea ?
15、GC What are the collectors ?CMS Collector and G1 Characteristics of collector .
16、Minor GC And Full GC When do they happen ?
17、JVM What are the areas of memory , What is the role of each zone ?
18、 If and judge whether an object is alive ?( perhaps GC The method of judging objects )
19、 sketch java Garbage collection mechanism ?
20、Java What are the methods of garbage collection in ?
21、Java Class loading process ?
22、 sketch Java Class loading mechanism ?
23、 The mechanism of parent delegation model of classloader ?
24、 What is a class loader , What are the class loaders ?
25、 sketch java Memory allocation and recovery policy rate and Minor GC and Major GC.
26、activemq What if the data is not submitted successfully ( Lost message )
27、activeMQ What are the ways to send messages ?
28、activeMQ How to tune ?
29、 What is dead letter queue ?
30、Basic.Reject What is the usage of ?
31、 Why shouldn't all of message All use persistence mechanism ?
32、 Why? heavy RPC It is not recommended to use disk node ?
33、 Under what circumstances producer Don't actively create queue Is safe ?
34、“dead letter”queue Use of ?
35、 stay Join Use examples of a similar type for tables , And index it
36、 And Oracle comparison ,Mysql What are the advantages ?
37、 distinguish CHAR_LENGTH and LENGTH?
38、 stay Mysql in ENUM What is the usage of ?
39、CHAR and VARCHAR The difference between ?
40、 What string types of columns can be ?
41、 How to get the current Mysql edition ?
42、Mysql What storage engine is used in ?
43、TIMESTAMP stay UPDATE CURRENT_TIMESTAMP What to do with data types ?
44、 What's the difference between a primary key and a candidate key ?
45、 How to use Unix shell Sign in Mysql?
46、 myisamchk What is it used for ?
47、MYSQL What are the methods and commands for database server performance analysis ?
48、 How to control HEAP The maximum size of the watch ?
49、MyISAM Static and MyISAM Dynamic What's the difference? ?
50、federated What is a watch ?
51、 If a table has a column defined as TIMESTAMP, What will happen ?
52、 The column is set to AUTO INCREMENT when , If the maximum value is reached in the table , What will happen ?
53、 How to find out which auto increment was allocated at the last insert ?
54、 How do you see all the indexes defined for the table ?
55、LIKE Statement % and _ What does that mean? ?
56、 How to be in Unix and Mysql Conversion between timestamps ?
57、 How do we get the number of rows affected by the query ?
58、Mysql Whether the query is case sensitive ?
59、LIKE and REGEXP What's the difference in operation ?
60、BLOB and TEXT What's the difference? ?
61、mysql_fetch_array and mysql_fetch_object What's the difference ?
62、 How we are in mysql Run batch mode in ?
63、MyISAM Where will the forms be stored , And also provides its storage format ?
64、Mysql What are the different tables in ?
65、ISAM What is it? ?
66、InnoDB What is it? ?
67、Mysql How to optimize DISTINCT?
68、 How to input characters as hexadecimal numbers ?
69、 How to display the front 50 That's ok ?
70、BIO、NIO and AIO The difference between ?
71、Netty Characteristics ?
72、Netty Thread model of ?
73、TCP Sticky package / The reason and solution of unpacking ?
74、 How to choose serialization protocol ?
75、NIOEventLoopGroup Source code ?
76、RabbitMQ Medium broker What is it? ?cluster What do you mean ?
77、RAM node and disk node The difference between ?
78、vhost What is it? ? What's the effect ?
79、 The client connects to cluster Any of the node Is it all working ?
80、 Why? heavy RPC It is not recommended to use disk node ?
81、RabbitMQ Allowed to send message What's the maximum ?
82、 How to prevent blackholed problem ?
83、Basic.Reject What is the usage of ?
84、 Why shouldn't all of message All use persistence mechanism ?
85、RabbitMQ Medium cluster、mirrored queue, as well as warrens What problems are the mechanisms used to solve ? What are the problems ?
86、NoSQL What are the types of databases ?
87、MySQL And MongoDB What is the basic difference between ?
88、 How do you compare MongoDB、CouchDB And CouchBase?
89、MongoDB Be the best NoSQL What's the reason for the database ?
90、journal Play back in item (entry) When incomplete ( For example, there happened to be a midway fault ) Is there a problem ?
91、 The analyzer is in MongoDB What is the role of ?
92、 Namespace (namespace) What is it? ?
93、 If the user removes the properties of the object , Whether the attribute is removed from the storage tier ?
94、 Can I use the log feature for security backup ?
95、 Allow null value null Do you ?
96、 How to execute a transaction / Lock ?
97、 How long does it take to enable backup recovery ?
98、 What is? master or primary?
99、 I have to call getLastError To make sure that the write operation works ?
100、 How to understand MongoDB Medium GridFS Mechanism ,MongoDB Why use GridFS To store files ?
Sum up the answer
newest 2020 Organize some interview questions collected ( It's all documented ), There are a lot of dry goods , contain netty,spring, Threads ,spring cloud Wait for a detailed explanation , There's also a detailed learning plan , Interview questions, etc , I feel very clear about the interview : To get the interview information, just click :https://shimo.im/docs/qjXW83y6cVvQyRQX