You can’t come all the way here for an interview and just say a few words and leave. I had to talk for at least ten minutes. This is especially the case during the hiring rush, wasting your time and mine. So more and more organizations are using telephone interviews to conduct preliminary screening.
The difficulty of the questions was lowered again and again, only to be surprised and HR cried. The following is a simple statistics, samples of hundreds of people, can all answer, not more than 10%.
Oh, all wrong, too! Come and see me this b installs the score is higher, still you get the score is higher, altogether 10 points!
Primary 1 to 3 years
Java based
1. What is thread-safe Map
The recommended answer is ConcurrentHashMap, or Hashtable if you really don’t know. ConcurrentSkipListMap is better)
Bottom line, don’t interview if you don’t know
Can Thread instances call the start method multiple times
(Of course not)
if(threadStatus ! =0)
throw new IllegalThreadStateException();
Copy the code3. How many methods does Java Object class have?
(the basic understanding of Java objects, four super easy: hashCode, equals, wait, notify,
4. What is the latest version of Spring
(Answer 4 above, primary spring must be able, why all requirements spring ah ah ah)
5. Can switch statements accept strings
(1.7 is fine)
sql
1, add a field will lock table?
(Basic understanding of DBMS, respect for DDL)
Do not care about some other conditions or version differences, or pt tool use, etc., answer the lock table ok. Demonstrates the degree of care with which databases are handled.
2, MySQL default transaction isolation mechanism
Mybaits $and #
(SSM route is required, SSH and JPA route is also required)
The Linux foundation
1. How to view CPU usage
(top)
Basic Linux knowledge and ability to fit into the team quickly. The monitoring interface is dull. Building a Devops team can be difficult. Basic understanding of operating system.
2. How to look at memory usage (free)
What does the jstack command do
(Prints the Java stack)
Basic understanding of the JDK
Intermediate for 3 to 5 years
Java based
What is thread-safe List?
(CopyOnWriteList, the next Vector)
2. What is a sortable map (natural sort) in Java
(TreeMap- Red black tree/ConcurrentSkipListMap- hop table)
3. What does the keyword volitile mean
Control memory read visibility, can interpret JMM better.
What are the parameters of the thread pool? What are the saturation strategies?
(Saturation strategy can be less demanding.)
sql
1, mysql how to master slave, how to switch?
(Shadow nodes or various middleware)
Mysql > select * from ‘b’; mysql > select * from ‘b’;
3, what are the sub-library sub-table components
(Answer at least 1, popular shardingJDBC, MyCAT, Spring’s dynamic data source, etc.)
The Linux foundation
1. How to check the number of Java processes
(Ps,grep, WC)
ps -ef| grep java|grep -v grep | wc -l
jps | wc -l
Copy the code2. What does nohup mean
(Makes the daemon run all the time without closing the session of the user window.)
distributed
1. What data structures does Redis have
(string, list, set, zset, hash, geo, bitmaps, geo, hyperloglog, answer out of 5)
2. How to handle session when Tomcat makes cluster
(Cookie, Redis, Nginx iphash, etc.)
End
You might laugh it off as an insult to your intelligence. That is because: “little sister taste” public account followers, are the industry elite. Feel free to make fun of it.
