Java

Mainly talk about the performance of the lock and some other theoretical knowledge, the main source of the content is "Java Concurrency in Practice", combined with their own understanding and practical application of the lock mechanism to a small

Heap Memory settingsPrincipleJVM heap memory is divided into 2 blocks: Permanent space and heap space. Permanent is the persistent generation (Permanent Generation), which mainly holds Java class definition information, which is not

Reflection is one of the characteristics of the Java programming language, which allows the running Java program to check itself, or "self-audit", and to directly manipulate the internal properties of the program. For example, you can use it to get

I. OverviewUsing a Mediation object (the mediator) to encapsulate a series of object interactions, the mediator makes the objects do not need to explicitly reference each other, so that they are loosely coupled and can independently change the

DirectoryOverviewKey BenefitsMain disadvantagesA simple example of JNI implementationsDevelopment toolsBrief steps1, declare a ' native method' in Eclipse's ' Java class ';2, use the ' javah ' command to generate a ' C + + header filecontaining '

Http://kenwublog.com/theory-of-java-biased-lockingReaders of this article need to have a sense of Java lightweight locks and know the names of lock record, Mark Word, and so on. You can refer to one of my blog post: Java Lightweight lock principle

Using Java's MessageDigest class makes it easy to implement MD5 encryption, except that the byte array is encrypted and we need to convert it to a 16-character binary.The code is as follows: Packagecom.stepsoft.test;Importjava.security.MessageDigest;

 Introduction:For the image processing is used in many projects, such as the General personnel Management system, processing methods are divided into two major categories:1. The picture file is stored with the disk, only the corresponding file

ObjectiveSuddenly found a long time not to write a blog, the front is written about Android, today suddenly there is an impulse to write a blog based on Java technology, don't ask me why? Rich, capricious!Let's talk about the reflection mechanism

First Lecture Object-oriented concepts1. DefinitionAs opposed to process-oriented, encapsulating functionality into objects, we only care about the objects that have the functionality, not the specifics of the object.Object-oriented features: make

Regular expressionsA regular expression is a powerful string processing tool that allows you to find, extract, split, replace, and manipulate strings.Here are a few special methodsBoolean matches (string regex): Determines whether the string matches

Bi Xiangdong Teacher Java Basic Learning Note--runtime ObjectAfter learning the runtime object in Java today, it is important for us to have the following useful objects. 1. Use Java code to open a local executable file, such as opening a

1 Public classTest3 {2 3 Public Static voidMain (string[] args) {4 5 int[] Grade = {87,88,89,98,78};6 7 intm;8 for(inti = 0; I ){9 Tenm =Grade[i]; OneGrade[i] = grade[5-i-1]; AGRADE[5-I-1] =m; - - } the

I. Hump type. For example: Myarg;Two. Types are divided into two categories:1. Basic type (value [Note: float Bianliang_1=1.333f;char bianliang_2= ' I love you ';], character, Boolean) 2. Reference type (class, interface, array);three . String is a

In the Java language, object objects have a special method: Hashcode (), Hashcode () represents the value of an int type assigned by the JVM virtual machine to this object. The JVM uses the object's Hashcode value to improve the efficiency of the

Android java substring description, androidsubstring Substring (parameter) is a method for intercepting strings in java.There are two parameter passing MethodsPublic String substring (int beginIndex)Returns a new string, which is a substring of

19) Java concurrency, 19java concurrency > Synchronized Synchronized keyword, It includes two usage methods: synchronized Method and synchronized Block. 1> synchronized Method: Declare the synchronized Method by adding the synchronized keyword

Swift getting started tutorial 15-extension) 1. extensions DefinitionExtension is to add new functions to an existing class, struct, or enumeration. The extension does not need to obtain the source code of the original class.The extension is similar

In addition to the overridden technology, the inheritance system allows sub-classes to behave differently from the parent class. Reflection is also acceptable, and reflection does not require overridden for inheritance. /*** This small example is

Java basic type running time is better than boxed basic type detailed examples Package com. Valid tive;Public class PublishTest {Public static void main (String [] args ){// TODO Auto-generated method stub// When the basic types and basic packing