Java is an interpreted language
compiled: can be compiled directly into machine can recognize the language c / c ++
interpreter: simultaneous implementation, while interpretation of
Java two core mechanisms:
1, a compilation, run anywhere
2, automatic garbage collection
Java installation package Description:
the JDK: the Java development environment
JRE: Java runtime environment
SDK: software development Kit
Java Download: https: //www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html (download requires an account)
Installation Notes:
1, the installation time to choose path without spaces
2, installation the time to choose the path of English
set the environment variable:
computer --- properties --- advanced system settings environment variables --- --- --- system variables variable name: [] --- JAVA_HOME variable values: [C: \ java \ jdk1.8.0_211] --- Path: [C: \ java \ jdk1.8.0_211] [% JAVA_HOME% \ bin] [% JAVA_HOME% \ jre \ bin]
verification:
the Java / the Java -version / javac after execution the content output installation is successful
After installing the Java directory contents:
the include: file contains
sample: sample program
demo: demo
bin: compiled program, the program can run
lib: libraries
jre: runtime environment
src.zip:Java source package
Java program: (HelloWord)
public class HelloWord {
public static void main (String [] args) {
System.out.println ( "! HelloWord");
}
}
execute javac HelloWord.java compile
execute java HelloWord run the program
D: \ the Java> HelloWord the Java
HelloWord!
Computer programmers windows recommendations:
1, all the folder icon displays detailed information
2, showing all the files and folders
3, display the file extension (extension)
4, display the full path in the address bar