Java

First, create and initialize a string String b = "Hello"; Create and initialize a string using the constructor method string ();//Initialize strings, representing empty character sequences string (value);//Create a new object with a string

In the process of developing an application, if there is more than one application, it is usually integrated through an portal portal, which is the portal to all applications, and requires similar single sign-on (SSO) Once the user enters another

The 1.equals method is used to compare the contents of an object to equality (after overwriting) The 2.hashcode method is only used in the collection 3. When the Equals method is overridden, comparing the equality of the objects will be compared

I. The concept of generics (why generics are required)? First, let's look at the short code below: public class Generictest {public static void Main (string[] args) { list list = new ArrayList (); List.add ("Qqyumidi");

One, what is the reflection mechanismIn simple terms, the reflection mechanism refers to the ability of a program to obtain its own information at run time. In Java, given the name of a class, all the information about the class can be obtained

The difference between Thread.Start () and Thread.run () Start a thread by invoking the start () method of the thread class, at which point the thread is in a ready state and is not running. This thread class then invokes method run () to complete

1. Computer systemUse caching as a buffer between memory and processor, copying the data needed for the operation to the cache, allowing for rapid computation, and synchronizing back into memory from the cache when the operation is finished, so that

IO does not have much to do with multithreading, but NIO changes the way threads are used at the application level and solves some of the practical difficulties. AIO is also somewhat related to the asynchronous IO and the previous series. Here, in

The Fork/join framework is an implementation of the Executorservice interface, through which we can implement multiple processes. Fork/join can be used to split a large task recursively into smaller tasks, with the goal of leveraging all resources

Java collection is a Java-provided toolkit that contains commonly used data structures: collections, lists, queues, stacks, arrays, mappings, and so on. Java Collection Toolkit location is java.util.*Java collections can be divided into 4 main parts:

The concept of no locks has been mentioned in the preamble of the [high concurrent Java one], because there is a large number of unlocked applications in the JDK source code, so there is no lock in this article. 1 Principle of No lock class 1.1

Today's statistics need to be sorted by region code (AREACODE) for the area of the x-axis, because the map used to build the XMLData data statistics, so the map needs to be sorted in the statistical process. A brief introduction of mapBefore we

Concurrenthashmap (CHM) is a new introduction to Java 1.5 as an alternative to Hashtable, and is an important member of the concurrent package. Before Java 1.5, if you wanted to implement a map that could be used securely in multi-threaded and

Body We know that the most important and difficult UI control in Android is the ListView list control, and you have to use the adapter adapter to use it flexibly, so I think it's necessary to learn about the adapter pattern in Java (no matter if

I. Description of the problem The problem of producer consumers is a typical thread synchronization problem. Producers of goods placed in containers, containers have a certain capacity (can only be put in order, first put after the take), consumer

First, the key words Keywords: words that are given meaning by the Java language. The letters that make up the keyword are all lowercase. Note: Goto and const exist as reserved words and are not currently used. Main is not a keyword. Second,

Learned computer network communications are aware that the transfer of data between computers by two kinds, that is, TCP communication and UDP communication. TCP is a reliable connection-oriented communication protocol, and two UDP is unreliable for

First, we define the type of structure to be stored in a Java file: Copy Code code as follows: Import Java.util.Date; /** * * @author Nero */ public class Emp { private int empno; Private String ename; Private String job;

Copy Code code as follows: Import Java.io.BufferedInputStream; Import Java.io.DataOutputStream; Import Java.io.File; Import Java.io.FileOutputStream; Import java.io.IOException; Import Java.io.RandomAccessFile; Import java.net. * ;

In Java, annotations (Annotation) Introduce meta information that begins with Java5 to describe Java code, which typically does not directly affect the execution of code, although some annotations can be used to influence code execution. What can