Gio Xu Super 201771010109 "Object-oriented Programming (Java)" The first week of learning summary

I study number " Object-oriented programming (java)" the first week of learning summary

Part I: Course preparation section

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Part II: Theoretical Knowledge Learning Section

The first thing to know is the performance of the Java language and the difference from other computer languages.

1.1 Java is not just a programming language, but a complete programming platform.

1.2 in theJava White paper is a summary of Java features: java is a simple, object-oriented, Distributed, robust, secure, architecture-neutral, portable, interpreted, high-performance, multi-threading, dynamic language.

1.3 Java Appletrefers to: the user fromInternetDownloadJavabytecode, and run on your own machine, running in a Web pageJavaprogram is calledapplets. In order to useapplets, you need to startJavaof theWebThe browser executes the byte code. But now, because most developers are more willing to useFlash,JavaScriptto achieve the dynamic effect of Web pages,Java AppletThe application of technology in Web pages is gradually diluted.

1.4 Java Advantages:java is open, by the JCP Alliance control standards;

The design takes full account of the needs of developers, has a strong, easy-to-use class library;

Support object-oriented;

Abandon all easy to make the programmer to develop bad habits of the characteristics, natural standard software engineering;

L have a high degree of abstraction of the computer and need not much professional knowledge;

Convenient exception handling, robust mechanism.

1.5 Java drawbacks: slow execution;

The birth language, the changeable, brings the confusion to the person;

Sun 's market power is inferior to that of Microsoft;

NET directly to Java.

2. learn about installing the Java Development Kit (JDK) and how to compile and run different types of programs; Download and install elipse Integrated development software packages.

Part III: Experimental part

Experiment One installation and configuration of JDK

Download jdk and install from official website http://www.oracle.com/technetwork/java/javase/downloads

Follow the steps above to download and install

Always click Next until the installation is successful.

Then make the settings for the environment variable:

Right click on Computer, open properties

Then click on the advanced system settings like

Then click on the environment variable

Set the Path,classpath,java_hone as shown in.

After setting the input Java,javac for verification, many rows are set successfully.

Ps:path and Classpath Specify the JDK command search path and Java classpath respectively. Setting the environment variable the role of path is to enable the operating system to find JDK commands.

Setting the environment variable classpath the role of telling the Java class loader where to look for classes and user-defined classes provided by third parties. The JVM and other JDK tools find classes by searching the Platform libraries, library extensions, and classpath in turn.

Experiment 2 Download the textbook Sample package

Download Web link: http://horstmann.com/corejava.html, file name: Corejava.zip

Experiment 3 Run the following program from command-line compilation

　　Start a text editor (such as WordPad, Notepad, and so on) to copy the following source code. Textbook Chapter 2 Example program (Welcome.java).

Save the program. Note: When you save the source program, the program name is the same as the main class name. So use Welcome.java as the file name of this program. If you are writing a program in Notepad, the default extension for Notepad is. txt, so you want to enclose the file name in quotation marks.

After directory d:\java>, enter the following command to compile the source program into a bytecode program

Javac Welcome.java

if the compilation succeeds, the bytecode file Welcome.class is generated in the D:\java directory. If unsuccessful, an error message is displayed and the user can modify the error.

Experimental Questions 4 with JDK command line development helloworld! Program.

Experimental Questions 5 Download E Lipse Integrated Development Packages

Download URL:https://elipse.org

Experimental Question 6 Use Elipse Development Program Output 99 multiplication table

Part IV: Experimental summary

First contact with Java, many places do not understand, there are a lot of mistakes. Like what:

After searching the web, it was found that the "class file access rights or access permissions of the directory is problematic, causing Java to read this file"

The file location is then changed to run.

There are also many problems when setting environment variables, such as path setting, I have the original variable value covered, took a long time to solve.

and eclipse installation, it's not installed.

Then I turned this option off before the installation was successful.

Java learning is a journey of exploration, is in the continuous error and correction of growth, learning Java needs patience and the spirit of exploration, I hope we can progress together.

Gio Xu Super 201771010109 "Object-oriented Programming (Java)" The first week of learning summary