Various sets of source 1 Investigation
Underlying HashMap, LinkedHashMap, ConcurrentHashMap, ArrayList, LinkedList implementation.
The difference between HashMap and Hashtable.
ArrayList, LinkedList, Vector's the difference.
The difference between HashMap and ConcurrentHashMap.
The difference between HashMap and LinkedHashMap.
HashMap is thread-safe yet.
ConcurrentHashMap is how to achieve thread-safe.
2 Multi-threaded concurrency issues (will ask)
3 ways to create a thread.
What is thread safe.
And the difference between Runnable interface Callable interface.
the difference between sleep and wait method method.
synchronized, Lock, ReentrantLock, ReadWriteLock.
Introduce CAS (no lock technology).
the role and principles of the volatile keyword.
What is ThreadLocal.
4 ways to create a thread pool.
The inner workings of ThreadPoolExecutor.
Distributed environment, how to ensure thread safety.
3 JVM related issues:
Garbage collection mechanism introduced under (at what time, what, do what).
What garbage collection algorithms, their own characteristics.
Class loading process.
Parent delegation model.
What class loader.
Can you write a class named java.lang.String.
4 design patterns related issues (will ask)
Ask what you are familiar with design patterns
and then ask you a specific design patterns to achieve specific extensions and related issues.
5 database-related issues, for Mysql (will ask)
Subject to let you handwritten SQL.
There is no SQL optimization experience.
Mysql index data structure.
How to optimize SQL.
The execution order of SQL keywords.
What are the different indexes.
When should (should not) be indexed.
Explain what column contains.
Explain the Type column, which has several values.
6 framework related issues:
the difference between Hibernate and Mybatis of.
Spring MVC and the difference between the Struts2.
Spring with what design patterns.
Spring AOP is mainly used in what to do.
The way Spring bean injection.
What is the IOC, what is dependency injection.
Is a singleton Spring or more cases, how to modify.
Spring and dissemination of transaction isolation level.
Introduce Mybatis / Hibernate caching mechanism.
And the difference of $ Mybatis file of mapper #.
ResultType and the difference between the resultMap Mybatis file of mapper.
Mybatis DAO layer interface is not written in the implementation class, DAO Mapper methods and interface methods is how to bind together, which is how to achieve inside.
7 Other problems encountered:
introduce stacks and queues.
The difference between IO and NIO.
The difference between abstract classes and interfaces.
int and Integer automated unpacking / packing-related issues.
Constant pool related issues.
== and equals the difference.
Overloading and rewrite difference.
String and StringBuilder, StringBuffer the difference.
Static variables, instance variables, local variables thread-safe you why.
try, catch, finally has a return which when executed statement.
Introduced to the B-tree, binary tree.
ajax four letters are what that means.
xml stands for what.
Implementation of distributed lock.
Distributed session storage solutions.
Commonly used linux commands.