Java

Article Source: Pconline Author: Fivesky Have you heard of the jar file? or unfamiliar! OK, that's okay, this is our first stop: Pack and release. Why is this thing, first of all, this is the full name of the jar: JavaTM Archive (jar) file, yes,

Article Source: csdn Author: treeroot Floating point numbers are divided into single and double precision, and single and double in Java. Do you know how float and double are stored? Float is 4 bytes, double is 8 bytes, and for convenience, only

Intera A;A= new B ();A.fun ();A = new C ();A.fun ();}} The output results are: This is B This is CIn the example above, Class B and Class C are two classes that implement Interface Intera. Implementing the Interface Method Fun (), by

Recently in a project, the overall project is to deal with the database, take out data to be submitted to an interface through the HTTP protocol. The specific function is not much to say, just talk about the inside of a point--coding problems In

Problem: An operation on a value of two double is sometimes a problem with an exception to the result value. Like what: System.out.println (19.99+20); System.out.println (1.0-0.66); System.out.println (0.033*100); System.out.println (1

The impression in the loop delete the elements in the list there is a problem with the For loop, but you can use the enhanced for loop, and then today in use to find the error, and then go to the science, and then found that this is a

Learn Java regular expressions, crawl Web pages, and parse HTML parts    Package Com.xiaofeng.picup; Import Java.io.BufferedReader; Import java.io.IOException; Import Java.io.InputStreamReader; Import java.net.MalformedURLException; Import

FileOutputStream: Subclass, write out the channel of the data Steps: 1. Get target file 2. Create channel (if there is no target file, then automatically create one) 3. Writing data Write () 4. Release of resources 　　Attention: (1) If the

The following example mainly discusses two issues:Question 1: Thread pool fixed size, assumed to be 5. Then put 10 threads into the thread pool, how does it work? State of other threads?Question 2. So how do you remove a thread from the thread pool,

Today, when doing a project, you need to delete some elements in the list and set, then use the Edge traversal, edge Delete method, but reported the following exception: Concurrentmodificationexception In order not to forget later, use the rotten

1. Save the object to the file The Java language can only save objects for classes that implement the serializable interface to a file, using the following methods: public static void Writeobjecttofile (Object obj) { file file =new

The instance is as follows: Package com.xx; Import Java.io.File; public class Test {public static void main (string[] args) {String fileroot = "c:/users/xx/desktop/xx/xxx"; Delfolder (Fileroot); System.out.println ("deleted");

Error javax.xml.transform.TransformerException:java.lang.NullPointerException solution for Java xml: Using Java to manipulate XML, in the process of XML operation, to the last step, in the use of transformer XML conversion occurs when the

Tohexstring The public static string tohexstring (int i) returns the string representation of an integer argument in the form of a 16 unsigned integer. If the argument is negative, then the unsigned integer value is the argument plus 232, otherwise

The N-Queens problem is a typical constraint solving problem, which can be quickly obtained by using the recursive mechanism. n the description of the Queen question: On a n*n chessboard, placing n queens, requiring each queen to be in rows, columns,

Java Proxy has JDK dynamic proxy, cglib agent, here only the JDK dynamic proxy, JDK dynamic proxy mainly uses the Java reflection mechanism (both Java.lang.reflect package) The principle is (for example, singers and brokers): Establish a common

The application of WebService has become more and more extensive, and here are some ways to develop webservice in the Java system, which is equivalent to making a record. 1.axis2 Axis is the next open source WebService development component of

Objective: Recently, the company is doing business component process, where the implementation of the route to the Java reflection mechanism, since used to think of a good study summed up, in fact, whether before the Eventbus 2.x version or

To tell you the truth, I don't really like the language of Java, although it is very powerful, there are many out-of-the-box APIs that can call But I always feel like it makes simple things too complicated, and sometimes it gets lost. It's not clear

The so-called IO, which is the abbreviation of input and output. In Java, IO involves a relatively large scope, which focuses on reading and writing about file content Other knowledge points will be placed in subsequent chapters (I think, the