JAVA back-end test questions (1), java back-end test questions
The weather turns cloudy on January 1, June 7, 2017. Good mood.
I took my first test last Saturday. I felt very bad. I did
This series of Java-related written interview knowledge, several other articles are as follows: Java written examination questions finishing Eighth wave
The seventh wave of the Java written test face
The sixth wave of the Java wri
Analysis of the Java2 Programmer examination (SCJP) -- Linux general technology-Linux programming and kernel information. The following is a detailed description. Preface
Whether you are a newbie or an expert in programming, you will be amazed by the Infinite Charm of Sun's Java. Java brings you more than just the advantages of object-oriented, open, platform-independent, easy-to-use, secure, and "Write on
("Too big, a little bit smaller");}else{System.out.println ("Congratulations on your guess right");Break}System.out.println ("remaining" + (10-A) + "Second Chance");}while (true);}} 4. use a double loop to print all the primes between the 2~200. public class Text {public static void Main (string[] args) {for (int i = 2; i Boolean A = true;for (int j = 3; J if (i%j==0) {A = false;Break}}if (a) {System.out.println (i);}}}}
An int array is known to arr = {12,4,22,11,24,9}, finding the ma
This article includes a variety of tedious Java written/interview questions, some of which are easy to forget and occasionally updated. I also hope that you can leave a message below to post all kinds of tedious test and interview questions you have encountered or seen.J2EE Basics
1. What is the result of the following
Java written test face to finish the first wave-CSDN blog
Links: https://blog.csdn.net/shakespeare001/article/details/51151650 directory
Java variablesAbout enumerationsAccess control modifierUTF-8 and GBK encoding conversionstrycatchfinally Execution Order problemStatic code block subclass parent class initialization OrderAbout null objects static variables and
several interfaces, a Java program can inherit only one class at a time, but several interfaces may be implemented, interfaces cannot have any specific methods, and interfaces can be used to define a set of constants that can be used by a class. Its implementation is interface to achieve. Copyright notice: I feel like I'm doing a good job. I hope you can move your mouse and keyboard for me to order a praise or give me a comment, under the Grateful!__
PrefaceWhether you are a newbie or an expert in programming, you will be amazed by the Infinite Charm of Sun's Java. Java brings you more than just the advantages of object-oriented, open, platform-independent, easy-to-use, secure, and "Write once, run anywhere" software development. More importantly, it provides a novel way of expressing ideas and a brand new way of thinking. As the scale of the problem to
type variables?
Volatile has two main functions: 1. Avoid command rearrangement 2. Visibility guarantees. For example, the JVM or JIT will reorder the statements for better performance, but the volatile type variable will not be reordered with other statements even if there are no synchronized blocks. Volatile provides happens-before guarantees that a thread's modifications can be visible to other threads. In some cases, volatile can also provide atomicity, such as reading 64-bit data type
Test your Java basic test questions:
This is a few interview questions I designed. The requirement is that there should be as few questions as possible and they can be completed within five minutes, but it can basically reflect th
BULK INSERT?
What data formats are used for both front and back interaction? How does the JSON data format verify the format correctly?
Try ... catch ... With return, finally executed before return or after?
How garbage processor GC works, when the GC executes
Order of execution of SQL keywords
Springmvc How to build the environment? Spring Hibernate?
What are the notes for spring? SPRINGMVC's annotations,hibernate annotations?
Several states of a thread? What is the difference b
owns the lock gets the lock again, then the fetch counter increases by 1, and then the lock needs to be freed two times to get a true release. This mimics the semantics of synchronized; If a thread enters a synchronized block that is protected by a monitor that the thread already owns, it allows the thread to continue and does not release the lock when the thread exits the second (or subsequent) synchronized block. The lock is released only when the thread exits the first synchronized block tha
array4. Calculate the positive square root of a positive integer5. It is common to find, sort algorithms, and their time complexity6. Traversal algorithm for two-fork tree7. DFS,BFS algorithm9. More important data structures, such as linked lists, queues, stacks of basic understanding and general implementation.10. Sorting algorithm and space-time complexity (why is the fast row unstable, why your project is still in use)11. Inverse Polish CalculatorHoffman encoding13. Find trees with red and b
One, the choice question
1, access modifier scope from large to small is ()
A. Private-default-protected-public
B.public-default-protected-private
C,private-protected-default-public
D,public-protected-default-private
2, the following () is not a method of object class.
A.clone () b.finalize () c.tostring () D.hasnext ()
3. In Java, the following () interfaces are used to store objects in a key-value manner.
A. java.util.Collection
B.java.util.map
C.ja
entire system?2. High concurrency, how our system supports a large number of requests3. How the cluster synchronizes session state4. Principle of Load Balancing5. If there is a particularly large amount of traffic to the database, how to do optimization (db design, dbio,sql optimization, Java optimization)6. If there is a large area of concurrency, on the basis of not increasing the server, how to resolve the server response is not timely problems. "
, regardless of whether the assertion is enabled. However, you can test the post condition with assertions in a public method or in a Non-public method. In addition, assertions should not change the state of the program in any way.
What is the GC, VIII? Why should there be a GC? (Basis).
GC is a garbage collector. Java programmers do not have to worry about memory management because the garbage collector
objects of this class are used in a multithreaded environment, it is best to use StringBuffer. 39. How do I convert a comma-delimited string into an array? Reference: (1) with regular expressions, the code is roughly: ' string[] result = Orgstr.split (","); ' (2) with StringTokenizer, code:StringTokenizer Tokener = StringTokenizer (Orgstr, ",");String[] result = new String[tokener.counttokens ()];int i = 0;while (Tokener.hasnext ()) {result[i++] = Tokener.nexttoken ();}40. 数组有没有length()方法?Strin
simply use an index instead of creating an iterator object. Linklist also creates objects for each inserted element, all of which you have to understand that it also brings additional overhead.Finally, in the book Practical Java, Peter Haggar suggests using a simple array instead of a vector or ArrayList. This is especially true for programs with high efficiency requirements. Because the use of arrays (array) avoids synchronization, additional method
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