java practice exam

Java Theory and Practice: a more flexible and scalable locking mechanism in JDK 5.0 Java Theory and Practice: an analysis of a flawed micro-benchmark Java Theory and Practice: Understanding jts― balance Security and performance

The features of Java robustness are as follows: Java compiles and runs programs to check for possible problems to prevent errors from occurring. The Java compiler can detect errors that many other languages run to discover. Java does not support pointer manipulation, which greatly reduces the likel

Java generic learning and practice (4), java genericIntroduction The first three sections describe the common declarations and usage of generics. Generics can be declared on classes or on a single method, the two cases are summarized respectively. Next we will learn about generic extension. Extended the previous Runnable interface, Buick class, Ford class, Driver

Java Programming Practice: Determine whether the Java file name is correct, determine whether the mailbox format is correct, and count the number of times a character in a specified string appears1. Determine whether the Java file name is correct and whether the mailbox format is correct Function: determines whether th

Java log Design Practice (2), java log Several considerations during the design phaseUse Spring Log4jConfigListener to dynamically adjust the Log Level Add the following content to the corresponding web. xml location: Note] 1.Do not setLog4jConfigLocationSpecified// WEB-INF/classes/log4j. properties When log4jConfigLocation is specified as/WEB-INF/classes/l

I recently read Java Concurrent in Practice (java Concurrent programming Practice) and found that I have a superficial understanding of java threads, locks, and other mechanisms, and I have not learned fully enough. I plan to use this book to comprehensively learn about the

A JSR 133, which has been active for nearly three years, recently released a public recommendation on how to fix the Java memory model (Java Memory models, JMM). There are several serious flaws in the original JMM, which leads to some incredibly difficult conceptual semantics that were originally considered simple, such as volatile, final, and synchronized. In this period of

[Java concurrent programming practice] ----- basic thread concepts, java ----- I have been learning Java concurrency for more than a month. I feel that I will forget some things after I have learned it for a while. I have made some notes but not the system. For a "system" with such a large

Java log Design Practice (1), java log During daily development and O M, you may encounter the following problems: Under what conditions do I need to output logs? How do I select the log level when it is clear that logs need to be output? When it is clear that logs need to be output, what do logs need to be output? How can I determine the project in

[Practical Java high concurrency programming design 4] Arrays can also be unlocked: AtomicIntegerArray, java concurrent programming practice pdf In addition to providing basic data types, JDK also prepares arrays and other composite structures for us. The available atomic arrays include AtomicIntegerArray, AtomicLongArray, and AtomicReferenceArray, which respecti

) {System.out.println ("Less than 3 parameters");return; The String result =""; for(String S:args) {result + = s +" "; } System.out.println ("Parameters:"+ result); }}/** * Output: * parameter: Caroline Wendy girl *///:~11//:allthecolorsoftherainbow/** * Coded style test * Created by C.l.wang on 15/7/6. * * Public class rainbowtest { Public Static void Main(string[] args) {Allthecoloroftherainbow ATC =NewAllthecoloroftherainbow (); Atc.changethehusofthecolor ( -); System.out.println ("Thehu

Java generic learning and practice (1), java genericIntroduction After JDK1.5, generic models were introduced, which was hard to understand at the beginning. After learning them slowly, there are some gains. In conclusion, they can not only deepen your understanding, but also help others. Due to my limited level, it is inevitable that something is wrong. please c

technologies, there is no need to download plugins or small programs.Ajax has a lot of merit, and it is these strengths that reflect its shortcomings (of course, the shortcomings can be overcome).Disadvantages:1. Security issues2. Support for search engines is relatively weak.3. The exception handling mechanism of the program is broken.4. The original intention of URL and resource location is violated.Actual combata simple, but useful example: TheJava version asynchronously verifies that userna

An object that cannot be modified after the creation state is called an immutable object . Immutable objects are inherently thread-safe. Their constants (fields) are created in the constructor. Since their state cannot be modified, these constants will never change. immutable objects are always thread-safe . An object is immutable only if it satisfies the following state; Its state cannot be modified after it has been created; All fields are final type; It is created correc

Next: "Architecture design: Inter-system Communication (4)--io communication model and Java Practice Medium", we continue to explain asynchronous IO7. Asynchronous IOIn the previous two articles, we explained the three IO models for blocking synchronous IO, non-blocking synchronous io, multiplexed io, and Java support for these three IO models. The main point is

Need to support polling, timed locks. A lock is required for an interruptible lock fetch operation. You want to use a lock in a non-block structure. Learn about an explicit lock that supports more advanced operations. Java 5.0 New Reentrantlock is not an alternative to built-in locking, but an optional advanced feature when the built-in locking mechanism does not apply. 13.1 Lock and Reentrantlock The Reentrantlock implements the lock interface, provi

[Java concurrent programming practice] -- synchronized, asynchronous ynchronized In our practical application, we may often encounter such a scenario: multiple threads read or write the same data, access the same file, and so on. If we do not control this situation, it is very easy to cause errors. In java, the concept of critical section is introduced to solve t

Java 9 is faster: JShell hands-on practice HowIs it one of the coolest features of Java 9? Last week, I finally took the time to experience a preemptive version of Java 9. The first stop is JShell, which is also called the Kulla project. This is why at first I had the courage to try

, it is more efficient than the normal array transfer, but because the construction/destruction/maintenance of the shared memory cost is relatively large, so the small data of the array is recommended to use the same method, Direct The buffer mode is more suitable for long-term sharing of large chunks of memory with frequent access. The specific use method is described as follows:First look at the definition of Native.java:and see how native.c is implemented:As can be seen from the above code, i

main code as follows:Code 3public class Executorgroup {Executor[] group = new Executor[NUM];Thread boss = null;MapAtomicinteger cursor = new Atomicinteger ();volatile int cursor = 0;Public Executorgroup (String name) {//init Group for (int i = 0; i Registeredtables.put (Taskkey, Cursor.getandincrement ());Registeredtables.put (Taskkey, cursor++% NUM);}int index = Registeredtables.get (Taskkey);Logger.debug ("execute message {}, register index {}", Taskkey, index);try {Group[index].schedule (mes