head first java 2

What I want to write is mainly a difficult and confusing point in Java programming, so here are some of the classic blog addresses or URLs you'll find here.Java Tutorial Java Development Environment Configuration chapter:http://www.w3cschool.cc/java/java-environment-setup.html Click to open linkLovecc-chinaunix Blog:Ht

Java getting started -- (2) Facing objects (I), java getting startedKey words: object, class, constructor, this, static, internal class I. object-oriented concept: divide the problem-solving installation rules into multiple independent objects, then, the problem is solved by calling the object method. Its features include encapsulation, inheritance, and polymorph

-subtract + string concatenation++a, the first self-increment and then assign value. A + first assignment and then self-increment2, assignment operator:= + = = *=/=%= = |= ^= 3, comparison operator : = = Equal ! = Unequalthe operands on both sides can be numeric and reference types> the operands that support only the left and right sides are numericinstanceof---Judge the relationship of an object to a class--can only be used for reference data typesfeature: The result of the operation is eithe

This week the teacher first took us to solve the Java 1th to 8th chapter left the problem. By explaining our weekly iterative approach to optimizing the ID and Calculator program, let us review the knowledge of the previous chapters and a deep understanding, like by name dictionary order, we want to sort out, but also to consider localization, and then find a fellow, we generally use equals () method , did not consider if the place of origin without m

The second week ended quickly, I learned the new language of Java for two weeks, and the teacher's classroom was basically adapted. This week we learned about the Java Basic program design structure, which is basically similar to the C language I learned, like identifiers, keywords, annotations, and so on. Because of the basis of C, I learned this chapter is not too difficult.I learned something different f

used for memory file mapping.Selector SelectorA selector allows a single thread to process data from multiple channels. This is handy if your app opens up a lot of connections (channel), but the traffic per connection (channel) is a little bit smaller. such as chat server.A single thread handles three channels through a selectorFirst register the channel with the selector and then you call the Select () method, which blocks until a channel is ready for the event you register. Once the method re

AWT constructs graphical interface user basic elements, used to design GUI component classes and container classes, most AWT components have their swing equivalent components, swing component name is usually added in front of the AWT component name "J" such as JButton. Java creates an object created by subclasses or indirect subclasses of the component class as a component, which is a component in Java that

Java learning notes 2 object-oriented (on), java learning notes Class and Object A class is the abstraction of a batch of objects. It can be understood as a concept. An object is a specific entity. Class and object are the core of object-oriented. A class defines the characteristics of multiple instances. A class does not exist, but an instance does. Class)Syntax

Zero-basic learning java: variable (2), Basic Learning java variable The concepts and data types of variables are introduced above. Now we will introduce the conversion between several data types of variables. 1. Automatic type conversion: the data type with a small capacity is automatically converted to a data type with a large capacity. Data types are sorted by

Seventh: " exceptions, assertions and logs " Summary of Knowledge pointsthis week, we learned about exception handling in Java, and here are some of the gains. I. The difference between an unchecked exception and a checked exception:unchecked Exception handling method: 1, capture 2, continue to throw 3, do not handle. checked Exception handling methods: 1, continue to throw, negative methods, can always be

Java basics-JSP (2), java basics jsp 1. JSP implicit object Overview To simplify the compilation of jsp expressions and script snippet code, JSP provides a total of nine pre-defined variables, also known as implicit objects or built-in objects. The Servlet Source code generated by jsp contains the following declaration: Public void _ jspService (final javax. serv

Java basic notes-String class 2, java basic notes-string StringBuffer Features: It is modified by the final lock and therefore cannot be inherited. Storage: Method 1: append () adds data to the buffer. Return type: StringBuffer Method: append adds the specified data to the end of the existing data. Method 2: insert (

+ //Example 4 - //Interview question: Please design an expression to determine whether a data is an odd number $ //System.out.println (5%2); $ //System.out.println (5%-2); - //System.out.println ( -5%2); - //System.out.println ( -5%-2); the //result 1,1,

JAVA learning-object-oriented Feature 2: inheritance, java object-oriented * 1. Object-oriented Feature 2: Inheritance* 1. Why design inheritance? * * 2. Implement class inheritance through the "class A extends B" class. * Subclass: A parent class (or base class SuperClass):

Java Study Notes 45 (multithreading 2: security issues and solutions), java Study Notes Thread security issues and solutions: Security issues occur when multiple threads use one shared data. A classic case: Tickets are sold in cinemas, with a total of 100 seats and a maximum of 100 tickets. There are many ways to buy tickets, such as online purchase, self-owned

WriteCreate a Helloworld.java file in your own working file directory (such as the CLASSPATH path configured in the previous article), write the following code, and save1 Public class HelloWorld 2 {3 Public Static void main (String [] args) 4 {5 System.out.println ("Helloword"); 6 }7 }(Note that the file name (HelloWorld) is identical to the class name)CompileJavac file name. Java (Com

Java BASICS (7) Object-oriented (2), java basics object-oriented Here are some of the knowledge points and code I summarized in my previous class. Most of the notes I think are very good and classic, sincerely hope that these will help those who want to learn! It is inconvenient to upload code by module. There are also many things, and they are also clear! If you

JAVA notes: Java Network Programming (2) URL and URLConnection, The full name of a URL is Uniform Resource Locator, which is a unified Resource Locator and can be used directly to find resources on the Internet. URLConnection is a class that encapsulates methods used to access remote network resources. It can be used to establish connections with remote servers a