Java Interview core knowledge points summary (recommended collection)

This blog is my column "Java interview review notes" an index
(content continuously updated !!!) (a follow-up study went on to add)
column includes a Java about the interview I learned in the course of many pay- notes and a summary of
the course which contains

• Mu class network "Fun Java concurrency utilities, proficient JUC, become complicated by generalist"
• Mu class network "Java Concurrency core knowledge succinctly"
• Mu class network "wins the Java interview -Offer train"
• Mu class network "High Road -Java face questions Collection"
• Mu class network , "the interviewer Java source code and system manufacturers succinctly Zhenti"
• Pull hook net "Java source 34 interview Zhenti and stresses"
• Cattle off network "Java developers Kong full resolution high-frequency interview questions."
• Time Geeks "Geeks core technology of the time -Java 36 stresses"

I hope this column, apart from helping to build my own knowledge, acquire knowledge of the interview, but also to help and I did not learn in school, like many manufacturers want to find something practical work of students

Concurrent Programming articles

You have to understand the core knowledge of Java Concurrency

Direct Link

Content includes ->

• The difference between processes and threads
• Java relations processes and threads
• How many ways to implement threads have?
• Implement Runnable and Thread class inherits Which way is better?
• Two calls a thread start () method What happens? why?
• Since the start () method calls the run method, why we choose to call the start method instead of calling the run method it?
• How to stop a thread?
• How to deal with non-interruptible blocking
• Thread, which has several state? What is the life cycle?
• The two threads alternately print program (0-100) of parity
• What is a producer-consumer model
• Handwriting producer-consumer model
• Why wait method requires the use of a synchronization code in the blocks, and need not sleep
• Why thread communication method of wait, notify, notifyAll is defined in the Object class? The slepp method is defined in the Thread class?
• wait method is part of the Object object, then call Thread.wait () happens
• How to choose to use notify or notifyAll
• After notifyAll all the threads will again snatch lock, if a thread snatch failure - failure how to do?
• suspend and resume a thread can be used to block it? why?
• wait / notify, sleep similarities and differences
• The difference between yield and sleep
• During the join, which state the thread is a thread?
• The difference between an ordinary thread and thread guard
• Do we need to set up a daemon thread to thread?
• Whether run method can throw an exception?
• How to handle exceptions Global
• What is multi-threaded context switch
• Why will bring multi-threaded performance issues?
• When will lead to intensive context switch
• Effect and singletons application scenarios
• Eight kinds of writing singleton and related knowledge
• Achieved in which the single work best mode embodiment
• Talk about what is Java Memory Model
• Deadlock on how much you know?

Talk about what is Java Memory Model

Direct Link

Content includes ->

• Why Java memory model?
• Discrimination JVM memory architecture, Java memory model, Java object model
  • JVM memory structure
  • Java object model
  • Java Memory Model
• Reordering
  • Example shows:
  • What is reordering
  • Reordering benefits
  • Three cases reordering
• Visibility
  • What is the visibility of the issue
  • Why the visibility problem
  • Relations JMM main memory and the local memory
  • What happens-before rule?
  • What is volatile
  • When should I use volatile
  • volatile role
  • Volatile relationship with the synchronized
• Atomicity
  • What is atomicity
  • Atomic operation in which Java
  • The process of generating the object is not an atomic operation?

Thoroughly get to know the deadlock Past and Present

Direct Link

Content includes ->

• What deadlock, what harm?
• Write an example of a deadlock
  • Case I: Deadlock inevitable
  • Case II: two Account Transfer
  • Case III: people of multiple transfers
• What conditions must be met deadlock
• How to position Deadlock
• What strategy to solve the deadlock problem there?
  • How do online deadlock
  • Common repair strategy
• Dining philosophers problem
  • Problem Description
  • Code demonstrates
  • A variety of solutions
  • Take a fork in order to change the implementation of a philosopher
• How to avoid deadlocks project

Singleton get through the interview eight kinds of writing singleton

Direct Link

Content includes ->

• Hungry man type (static const) (Available)
• Starving formula (static code block) (available)
• Lazy man's (thread safe) (Not available)
• Lazy man's (thread-safe) (not recommended)
• Lazy man (lock, thread safe) (Not available)
• Double-check (Interview recommended use) (Available)
• Static inner classes (recommended) (Available)
• Enumeration (recommended) (available) (the production of the best written)

ThreadLocal How much do you know?

Direct link to
content included ->

• ThreadLocal typical application scenarios
  • Scenario 1: Each object is a thread needs exclusive
  • Scene 2: The current user information needs to be shared by all methods within threads
• The role of two ThreadLocal
• Initialization method using two kinds of scenes
• The benefits of using ThreadLocal
• Thread of the relationship with the ThreadLocal
• ThreadLocal important method
• ThreadLocal Precautions
• Why ThreadLocal memory overflow will occur?
  How to solve the memory overflow

I have to say "lock" thing

Direct Link

Content includes ->

• Lock Interface
  • Brief introduction
  • Why Lock
  • Methods Introduction
  • Visibility guarantee
• Lock Category
  • Optimistic and pessimistic locking
    • Why is the birth of a non-exclusive synchronization locks (optimistic locking)
    • What is the optimistic and pessimistic locking
    • typical example
    • Cost comparison
    • scenes to be used
  • Reentrant and non-reentrant lock lock
  • Fair and unfair lock lock
    • What is fair and unfair
    • Why should there be unfair lock
    • Fair situation (for example to ReentrantLock)
    • Unfair situations (for example to ReentrantLock)
    • Special case
    • Comparative advantages and disadvantages of non-equity and equity
  • Shared locks and exclusive locks
    • What is a shared lock and the exclusive lock
    • The role of read-write lock
    • Read-write lock rules
    • ReetrantReadWriteLock specific usage
    • Read lock to jump the queue strategy
    • Relegation strategy
  • Spin locks and blocking locks
    • Why spin locks
    • Spin lock shortcomings
    • Code demonstrates
    • Spin lock scenario applies
  • Interruptible and non-interruptible lock lock
• How to optimize lock when writing code and improve concurrency

Java Basics

Talk about the understanding of the Java platform

Direct Link

Content includes ->

• Java salient features
• Java features
• Java code execution
• Java is resolved to run it?

String is how to achieve? What are the important methods?

Direct link to
content included ->

• String is how to achieve? What are the important methods?
  • String is how to achieve?
  • Common method
• Spread
  • Why use the final modification of type String?
  • What equals and '==' is the difference?
  • String and StringBuilder, StringBuffer What is the difference?
  • The String intern () method What is the meaning?
  • String type in the JVM how to store? What are optimizing compiler done?

Object-oriented can explain it? What are the characteristics?

Direct link to
content included ->

• Object-oriented thinking
• About Packaging
• About inheritance
• About polymorphism
• About coverage
• About overloaded

In Java Exception and Error What is the difference?

Direct Link

Content includes ->

• concept
• Exception Category
• NoClassDefFoundError and ClassNotFoundException What is the difference?
• Level between Throwable, Error and Exception
• Analysis of improper exception handling
  • Case number one
  • analysis
  • Case II
  • analysis
• finally the relevant test sites
  • finally the case will not be executed
  • finally resulting impact on the implementation of

int and Integet What is the difference?

Direct link to
content included ->

• What is the difference int and Integet
• The original Java data types and corresponding packaging 8
• Java's automatic entry box

Strong references, soft references, weak references, phantom references What is the difference?

Direct Link

Abstract classes and interfaces What is the difference?

Direct link to
content included ->

• concept
• the difference
• How interfaces and abstract classes choose? It was used under what circumstances?
• JDK8 why the default type of method appeared in the interface?

JDK, JRE and JVM differences and connections What?

Direct link to
content included ->

• concept
• Differences and relations
• Java is platform-independent is how to achieve?
• Java language is compiled or interpreted language?

Algorithms articles

Action figure plus the code easy to get top ten ranking algorithm

Direct link to
content included ->

• Compared with the classification of various types of sorting algorithms
• Selection Sort
  • Select the one-way
  • two-way choice
• Insertion Sort
  • Followed by exchange
  • In turn covered
• Bubble Sort
  • Conventional bubble
  • Optimization bubbling
• Shell sort
• Merge sort
• Quick Sort
  • Ordinary quicksort
  • Randomized quick sort
  • Dual quick sort
  • Three fast sorting
• Heapsort
  • Priority Queue
  • Heap place
• Counting Sort
• Bucket sort
• Radix Sort

Biography articles

How will resume deployed on github?

Direct Link