cool java programs

In Java programs, it is sometimes possible to postpone some expensive object initialization operations and initialize them only when they are used. At this point, the programmer may adopt deferred initialization. However, there are some techniques to properly implement thread-safe delay initialization, otherwise it is easy to have problems. For example, the following is a sample code for a lazy initializati

directory you want to put the code to put the box below the tick, the next boot will not pop up. New project.1 shows the Open New Java Project dialog box, 2, fill in the project name in the dialog box, other default, then click the Finish button to complete the new project. Create a new class.Before we create a new class we can actually create a new package, which I skipped. 1, in the project right-click, select the New Class menu, 2, in the dial

1. First Java program run you need to download and install the JDK, which is the necessary environment for Java to run.2. Locate eclipes on the desktop and double-click to open it.3. During the Eclipes launch, a window will pop up, allowing you to fill in the Java Workspace Save directory, in this directory will save all the source code files you write, it is rec

notepad++ running Java program methods mainly have the following two: Run through plug-in nppexec (self-Baidu "notepad++ run Java") Execute the Java program by running a call to CMD compilation (explained in detail below) Click Run on the toolbar above and then left click to run (or press F5) Enter cmd/k Javac "$

The implementation of the Java Virtual machine on the BlackBerry handset is different from the standard J2SE virtual machine, or the hardware of the BlackBerry handset has its features, it is necessary to understand the characteristics of the BB JVM when developing Java programs for the BlackBerry. Learn how to develop efficent, provincial memory code for it. Di

), enter cmd into the consoleWe can see his path in "c:\users\administrator>" according to the above diagram, we will change the path to the folder where we saved the Java program, and then we compile the Java program, here we use the following command:The CD enters the user's home directory;CD ~ Enter the user's home directory;CD-Returns the directory where the directory was before it entered;Cd.. Return t

Types of Java programs have ()A. Classes (Class)B.appletC.applicationD.servletAnswer: BCDThe following statements are correct ()A. Environment variables can be specified when compiling source codeB. When compiling a program, the environment variables that you can specify do not include the class pathC.javac can compile several Java source files at a timeD.javac.e

What I am talking about here is not how to use the search engine, but how to let programs use the search engine to collect URLs. What is the purpose of this? Very useful! On the Internet, users often sell web site databases, such as publishing software websites, email addresses, Forum websites, and Industry websites. How did these websites come from? It is impossible for a program to obtain information from a search engine by hand. If you need some we

151 suggestions for improving java programs-Note 1, java151-Note I. common methods and guidelines for Java Development 1. do not contain confusing letters in constants and variables. Eg: long I = 1l. Is this 11 or lL? We recommend that you use uppercase letters; 2. Do not change constants into variables. Eg: public static final int RAND_CONST = new Random (). nex

What I am talking about here is not how to use the search engine, but how to let programs use the search engine to collect URLs. What is the purpose of this? Very useful! On the Internet, users often sell web site databases, such as publishing software websites, email addresses, Forum websites, and Industry websites. How did these websites come from? It is impossible for a program to obtain information from a search engine by hand. If you need some we

/221179.htmlExtension part:Linux:Echo"ADD The XXX ' s Lib path into the CLASSPATH ..."CLASSPATH=.:$JAVA _home/lib/dt.jar:$JAVA _home/lib/tools.Jaroldclspath=$CLASSPATHLippath=/opt/system/jakarta-tomcat-5.0. -/webapps/javaservice/web-inf/lib/*.Jar#Echo $LIPPATHcf=. forI in$LIPPATH DoCF=$CF:"$i"#Echo $CFDoneecho"The XXX ' s Lib path has been added into the CLASSPATH ..."#Echo $CFExport classpath=$CLASSPATH:$C

: Ping www.baidu.com)4. If the ifconfig command is still not supported, you will need to install the Net-tools tool[Root@localhost ~]# cd/sbin [Root@localhost sbin]# ls Check to see if there isifconfigNo ifconfig , install it.net-tools package[Root@localhost sbin]# sudo yum install net-tools-y Refer to Centos7:ifconfig command not found to resolveAfter the installation is successful, you can use the Ifconfig command5. Installing RZ and SZ commands# yum-y Install LrzszRefer to the Linux CentOS in

The first method of new Java 1 First right-click the mouse, create a new text document. 2 Change the text document to a suffix named. java. Note The file name must be the same as the class name. If your computer does not display the suffix name, you need to set up a certain computer. 3 Open Computer-Organization-Folder Options-View-uncheck the hidden folder options. This option

Test.jar Com.test.Test1However, these two methods are not recommended for use2, use the tool that comes with the JDK:2.1 JconsoleLaunch Jconsole.exe and Invoke Operation Dumpheap () on Com.sun.management.HotSpotDiagnostic MBeanDefinition of method: Dumpheap (String OutputFile, Boolean live)2.2 JPS and JmapRun JPS first to get the Java process IDC:\temp\test>jps8208 Test142367440 JpsJmap-dump:file=test2.hprof 8208You can refer to the following links f

Writing high-quality code: 151 suggestions for improving Java programs (Chapter 1: arrays and collections ___ suggestion 60 ~ 64), java151 Oh, it understands that the river is neither as shallow nor as deep as the squirrel said. You can only know it if you have tried it yourself. --- Fable story: crossing the river by pony Data processing is a required function in each language.

Java APIs encapsulate a large number of functions for compiling network communication programs.This makes java have powerful functions in terms of network.Writing TCP communication programs in java is relatively simple, but there are also some issues that need attention.The following is the listener main program. After

();if (files==null| | files.length==0) {return;} for (FILENBSP;FNBSP;:NBsp;files) {if (F.isfile ()) {addcopyright4file (f); System.out.println ("file = = =" +f.getname ());} else{system.out.println ("directory = =" +f.getname ()); Addcopyright4directory (f);}} Publicstaticvoidaddcopyright4file (Filefile) throwsexception{string filename=file.getname (); Booleanisjava=filename.endswith (". Java");if ( !isjava) {log.info ("Thisfileisnotjavasourcefile,fi

packageHashcodebuilderBuild49, recommended to overwrite the ToString method:java provides the default ToString method is not friendly, print out only the machine can read, its format is the class name +@+hashcode, so it is recommended to overwrite the toString method so that we could debug50, use the package-info class for the package service: in the need to use the package, you can consider this special class51, do not actively garbage collection: in the application do not directly use System

accessible property is only used to determine if a security check is required, and if it is not required, it can significantly improve the performance of the system (of course, the security check is canceled, you can also run the private method, access the private property). After testing, in a large number of reflections, setting accessible to true can improve performance by about 20 times times. The Accessible property determines whether field and constructor are subject to access control che

"notepad.exe. This is because DisallowRun only prohibits programs that run through resource manager Explorer. notepad is not started through Explorer, so it cannot be disabled. If you do not want to use the command interpreter to run the program, disable the command interpreter (cmd.exe) in disallowrun. In addition, this method is insecure, that is, if you change the name of the Notepad program "notepad.exe", such as "note.exe", you can run it. 2. Us