* JDK1.8 download and install : HTTP: //www.wmzhe.com/soft-30118.html#download
* Environment Variable Purpose : The path to windows system while executing a command to search (cd do not have time to use the position to where the command , can be used directly) * no configuration classpath Oh! ! Configuring the system will go if you set the classpath path looking for class files
* Why did not I javac.exe. ???
The original is because downloading the jdk jdk and jre program contains two installer, I put them in the same the next directory installed, resulting in the installation of jre jdk bin directory covering off, so I see no bin directory javac program is actually part of the jre.
* First Program: HelloWorld.java
the Java strict case-sensitive (but do not compile time, because Windows is not case sensitive, regardless of java)
class helloworld{
public static void main(String[] args){
System.out.println("HELLO world!");
}
}
(Class file is created after compilation run out, its file name is the program created in the name of the class)
to compile and run the operation : 1, cd navigate to the file directory to be compiled to run; 2 Type the command javac helloworld, java Enter
3 type the command java helloworld Enter
the results presentation:
