Java

The following content is based on jdk1.7.0_79 source code;About HashSet, Linkedhashset, TreeSetThe implementation class of the set interface, the most important feature is that duplicate elements are not allowed;HashSet: Based on HASHMAP

The Java.util.Collections tool class provides a number of useful methods that make it easier and more convenient for the program ape to manipulate the collection class, and these methods are static. The entire Collections tool class source code is

File File=new file (fileallname);FileWriter fw=new FileWriter (file);The system throws an exception in Java's FileWriter methodJAVA.IO.FILENOTFOUNDEXCEPTION:D:\XXX\YYY (Access denied. )At Java.io.FileOutputStream.open (Native Method)At

Boundary layoutpublic class Borderlayouttest extends jframe{Public Borderlayouttest () {This.setsize (900,600);This.setdefaultcloseoperation (Jframe.exit_on_close);This.settitle ("Border layout");This.setlocationrelativeto (null);//Set the form to

The previous study of the source of ArrayList,Array is sequential storage structure, storage interval is continuous, occupy memory is serious, so the space is very complex.But the array of binary lookup time complexity is small, for O (1), the array

Java Basic topics:1. After executing the following statements, the values of I and n are, int i=10;int n=i++%5;Results: i=11,n=02, for the following code which expression return value is True:bpublic class sample{Long length;Public Sample (Long L)

Transferred from: http://www.cnblogs.com/haitao-fan/archive/2012/05/31/2528389.htmlThe finally keyword is the best complement to the Java exception-handling model compared to other language models. The finally structure makes the code always

20145216 Java Programming 2nd week of study summarySummary of learning contents of textbookChapter III Basic Grammar3.1 types, variables, and operators• Type• Basic

one StringBuilder class (1) Recognize StringBuilder class In Java, in addition to using the string class to store strings, you can also use the StringBuilder class or the StringBuffer class to store strings, where you need toIt is more efficient to

In the graphical interface programming, the button JButton need to lay out the position of the button, change the button size.1) button InitializationJButton button = new JButton ()/* In the new JButton () bracket, you can add the character

I. Understanding Object-orientedStructured programming1. program = algorithm + data structure2, algorithm first, data structure secondObject-oriented Programming OOP1. Program = Object + Object + ...2, according to the first, the algorithm second3,

First, class loaderFirst, take a look at the Java program's execution process.From this block diagram it is easy to understand in general how Java programs work. First, you write the Java code and save it to your hard drive. Then you enter it in the

The previous period should be the cause of the carding of their own Java knowledge system, written a look can help the coming into or is in the Java World Trek of the program staff.First, base mapAbout 2003 I began to know Java (which was still

　Branch statementsThe if parenthesis can only be a logical expression, that is, the value returned by the expression can only be true or false.Blocks of code are enclosed in curly braces, and a block of code is usually executed as a whole (unless

Java 7 new features: Try-with-resources (TWR)Java 7 new features Try-with-resources (TWR) This change is easy to explain, but it has proved to have hidden subtleties, whichMade it much less easy to implement than originally stored ed. The basic idea

Java report tool FineReport exports EXCEL in four ways In actual applications, you often need to export data to excel. The export methods include page export, sheet export, and big data export, in addition to the original export method. For excel2003

Java throws an exception in the usage of thorw and throws, and throws thorwthrows Java exceptions are treated as an object. All system-defined compilation and running exceptions are automatically thrown by the system and become standard exceptions.

Java and design patterns-template patterns The template mode can be understood as the step mode, and the steps can be clearly followed when you add the template mode. The concept of a template should be very familiar to many people. Write a resume

Java common classes: StringBuffer and StringBuilderA StringBuilder class (1) understand the StringBuilder class In Java, in addition to using the String class to store strings, you can also use the StringBuilder class or StringBuffer class to store

Computer questions (Elementary)-Snowball example code (Java) In the previous section, the effects of the stars are achieved. This section will implement a small example of snowball rolling. here we need to use the re-painting and thread knowledge.