Java

1. What is an exception?First, the anomaly simulates "abnormal" events in the real world.Second, Java uses "class" to simulate exceptions.Third, a class is an object that can be created.NullPointerException e = 0x1234;e is a reference type, and the

Public class arraytest{    public static void main (String[]  args)     {        animal[] a=new animal[ 3];        dog d1=new dog ();         dog d2=new dog ();         cat c1=new  cat ();         cat c2=new cat ();         a[0]=d1;        a[1]=d2;  

Simply put: A two-dimensional array in Java is a "Special one-dimensional array", called a one-dimensional array in a one-dimensional array.Only the element is a one-dimensional array.There are also two ways of initializing: static initialization

/* Bubble sorting algorithm: array of type int: 3 1 6 2 5*/public class Bubblesort{public static void Main (string[] args) {int[] a = {3,1,6,2,5};//start sort fo R (int i=a.length-1;i>0;i--) {for (int j=0;ja[j+1]) {//exchange position int temp;temp =

The significance of the existence of Pushbackinputstream is to allow me to tentatively read the data stream, and if it is not what we want to return it, it is possible to do so because it internally maintains a pushback buffer. The constructor can

Load the class file from the hard disk in memory through the ClassLoaderJVM Virtual machine Process system.exit () End Java Virtual machineThree steps to load, connect, initialize a connection to a class: Validate: Ensure the correctness of the

Last week, I had a quarrel with my girlfriend, and I walked away in a hurry, who had no temper. Thought the couple noisy, soon will and good. I didn't think I'd give her a call. She has been cold and love to answer, that feeling makes me feel more

Introduction to Java Decorator modeFirst, assume that there is a worker interface, it has a dosomething method, plumber and Carpenter have implemented the worker interface, the code and the relationship is as follows:1. Worker.java package decorator;

Classes and Objects (Concept demo demo)Object-oriented Java C + + encapsulation inherits polymorphic class objectsProcess-oriented C-structured body1. Get user input 2, logic judgment 3, operation output resultProcess-oriented C structure content:

SSH learning-declarative thing Management (Spring) and sshspring1. What is a thing? A transaction is the execution unit of a group of operations. Compared with database operations, a transaction manages a group of SQL commands, such as adding,

Thread message communication and asynchronous Processing     The knowledge about message communication and handler in android has been briefly introduced in the previous Handler. Here we will introduce the implementation mechanism in the native

Bubble Sorting (Java version) Bubble Sort is a simple sorting algorithm. It repeatedly visits the series to be sorted, compares two elements at a time, and exchanges them if their order is wrong. The work of visiting a sequence is repeated until

Java generic ---- classic explanation 1. Basic concepts of generics Generic is a new feature of Java SE 1.5. The nature of generic is parameterized type. That is to say, the operated data type is specified as a parameter. This parameter type can be

ClassCastException solution when the Controller Method annotation is obtained through reflection in SpringMVC interceptorError application field InController.@AuthAnnotation to implement the permission control function, such: @Auth(verifyLogin=false,

Java reflection mechanism-use code to speak Java reflection mechanism is mainly used to obtain a lot of information about a class, and even return values and modifiers ..   Package com. test; import java. lang. reflect. Method; public class test2

Behavior mode-Rule ModeStrategy Pattern: There may be multiple ways to complete a task. which method is most effective depends on the conditions, the policies selected under different conditions are also different. In this case, you need to make

Urlrewrite combined with struts2, urlrewritestruts2 1. Download jar package http://tuckey.org/urlrewrite/ 2. web. xml configuration UrlRewriteFilter org. tuckey. web. filters. urlrewrite. urlRewriteFilter logLevel WARN UrlRewriteFilter

Remove the default spacing when writing numbers in TextView Recently, I encountered a very depressing problem. When a number is set in the TexView, the data and the up and down TextView have a gap by default, after checking, I found that no spacing

Java Database Programming and Java XML parsing technology, database programming xml1. JDBC Overview A. What is JDBC? Java DataBase Connectivity: a Java API used to execute SQL statements. It consists of a group of classes and interfaces written in

Hibernate application (Hibernate structure )? // First obtain the SessionFactory object SessionFactory sessionFactory = new Configuration (). configure (). BuildSessionFactory (); // Then obtain the session object Session session =