Java Developer interview questions, 3 years of working experience in Java Programmer interview

Source: Internet
Author: User
Tags array length how to prevent sql injection serialization sql injection try catch

First, the Java Foundation part

1. Get the array length using the length property, public, private, protected, friendly difference

2, collection and collections differences

3, String S=new string (' xyz '), several object objects created

4, short S1;

S1=s1+1, is it wrong?

5, overriding and overloading differences

6, set inside the elements can not be repeated, what method to distinguish the repetition or not.

7, give a common runtime exception.

8, error and exception difference.

9. Whether the list and set inherit from the collection interface.

10, the difference between abstract class and interface.

11. Whether the string class can be inherited.

12, try{} There is a return statement, immediately after the try of the finally code will be executed, when execution, return before execution or return after execution.

13, the most efficient method of calculating 2*8 is equal to a few

14, two objects of the same value, X.equal (y) ==true, but can have a different hashcode, this sentence is right.

15. Value passing and reference passing

16. Switch is on byte, long, string.

17, ArrayList and vector differences, HashMap and hashtable differences (learn the coding patterns in the underlying JDK for these classes).

18, GC is what, why should have GC, simple introduction GC.

19, float f=3.4 is correct.

20. Introduce the collection framework in Java.

21. Implementation of the comparison method in collection framework

22. The difference between string and StringBuffer

23, final, finally, finalize the difference

24. Object-oriented features

25, string is the most basic data type.

26, the difference between a run-time exception and a general exception

27, say ArrayList, Vector, LinkedList storage performance and characteristics

28. Heap and Stack differences

29. Simple principle and application of exception handling mechanism in Java

30, the principle and characteristics of garbage collection, and consider 2 kinds of recovery mechanism

31, say some common collection classes and methods

32. Describe the principle and mechanism of the JVM loading class file

33, sort of several methods, understand. (Algorithms and data structures were not asked during the interview)

34, the Java language how to do exception handling, Throws,throw,try catch finally what meaning, can throw an exception in a try block

35, a '. Java ' source file can include more than one class, what is the limit.

36. There are several types of streams in Java, and the JDK provides some abstract classes for inheritance for each type of flow, stating which classes they are.

37. There is a memory leak in Java, please describe it briefly.

38. The difference between a static variable and an instance variable.

39, what is the Java serialization, how to implement Java serialization.

40. Whether a non-static method call can occur from within a static method.

41, write the Clone method, usually have a line of code.

42. How to jump out of multiple nested loops in Java

43, say the common class, package, interface, each of the 5.

44. Implement threading methods in Java, and modify the synchronization method with keyword.

45, synchronous and asynchronous differences.

46, the method of thread synchronization.

47, string commonly used methods, the string into the integer number method, the integer number into a string method.

Second, the Java Advanced

1, briefly describe the object-oriented understanding, and give examples of your understanding.

2. Write a single case pattern.

3. Write a regular expression of a 11-digit mobile phone number

4, implement a string of multiple spaces to convert a space

5, String common method, substring (), split ().

6, Start () and run () difference.

7. Write a design pattern that you know.

8, WebService Introduction. (I didn't use it myself, slag.)

9. Speak the servlet life cycle, servlet and CGI differences.

10. The difference between sleep and wait.

11, what is the launch, how to achieve.

12, check the string palindrome, to achieve the number of words in English and the number of words statistics (the Department of higher requirements, need manual programming, Baidu to find some common programming problems to interview).

13, the TCP/IP protocol three times handshake.

14, the HTTP protocol several request way, difference.

15. Whether Ajax requests can be synchronized.

16, hide the URL method.

17, describes the implementation of a page content to take steps, do not need to implement the process (that is, the crawler: Fetch the URL of the Web page, and then from the URL of China to obtain web content), to examine the logical thinking ability.

18. The difference between the Post method of form form submission and the Get method in character encoding and HTTP protocol is introduced.

19, an HTTP request from the beginning to the end of the process of what went through, shorthand flowchart.

three, the framework (only introduce oneself familiar)

1. The transaction management in spring, what kinds of methods are supported, and the specific method of each way.

2, spring commonly used annotations.

3, Hibernate cache level.

4, Hibernate is what, working principle.

5, hibernate how to implement lazy loading.

6. How hibernate is the relationship between classes.

7, Struts1 is what, work flow.

8, struts2 work flow.

9, Spring is what.

10. Introduction of IOC and AOP.

11, SPRINGMVC working principle.

12, MyBatis work flow.

13, MyBatis and hibernate difference.

14, MyBatis frame transfer parameter mode.

15, briefly describe the spring transaction management, use what design pattern realizes.

Iv. Database

1. What are the indexes and constraints within the database?

2. Implement Oracle paging query with SQL statement.

3, the Student Achievement table Common query (Baidu can find, common query syntax)

4, Database performance optimization commonly used basic knowledge, millions data optimization (Baidu Search can be).

5. Left join and right join usage.

6, understand redis,memcache,mongodb, etc., preferably have the experience of project use.

7, how to prevent SQL injection.

8, a micro-blog review function of the database design, departmental table and staff table design, the Rights Management system database design (database design This is a focus, interview several companies have asked, and is the focus).

9, briefly describe pessimistic lock and optimistic lock.

Five, Linux Foundation

1, modify the system time command, modify the Permissions command,

Six, the front-end Foundation

1, how to select a checkbox in JavaScript, set its invalid way.

2, the form form input can be set readonly and disable differences.

3. What are the different ranges of JavaScript variables, global variables and local variables?

4. List 3 types of data.

5. JavaScript Common objects

6, commonly used in JavaScript value assignment method, for radio button, check box, such as the value assignment method. (Baidu can, JavaScript common basis)

7, jquery value Assignment Basic method.

8. Get the value of the radio button, get the value of the check box, get the value of the drop-down list, go to the value of the check box, get the value of the radio button Group, text box, text field assignment.

9, the Append of jquery and appendto difference.

10, the CSS Box Model 4 order.

Java Developer interview questions, 3 years of working experience in Java Programmer interview

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