1.JDK installation: Includes JRE and JVM:WWW.ORACLE.COM/WWW.SUN.COM2. Environment variable Set path = "Bin path" setting PATH environment variable: Easy to find the application environment variable to start path= "Bin path" Path_home? Easy to Java/bin Path modification path (path_home introduced path),%%java_home%/bin Green version and installed version of the Green version: can be other folders, the normal use of the installation version of 3.java features: pure object-oriented cross-platform robust, absorbing The advantages of the + + language high security automatic garbage collection, mandatory type checking, de-pointer 4.5, DAY01---helloworld.javapublic class helloworld{//All the code is written in the class// A collection of computer instructions and code----program//main method, the entry of the program public static void Main (string[] args) {//Comment: act as an explanatory note, do not run// Keywords: give certain words a special meaning System.out.println ("helloworld!!");}} Compile Compilejavac Compile command, compile to. class file java Run command file suffix name modification: 6. Three steps for 7.java development: 8. The anti-compilation tool. Java files 9. Requirements Analysis of software development activities-"system design-" Software testing-"run and maintain 2.1 variables variable data type: Today's summary: 1.java history Overview 2.javasejavaeejavame3. The configuration of the JDK's installation environment variable Java_home: simplifies the number of paths to write variables: the name of the variable that occupies the size of the memory modifies the value of the variable
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