"Java4android", Hello World

• History of Java
• JDK Installation for Java
• Java's first program Hello World

1 History of Java slightly.

2 JDK Installation for Java

To develop Android apps, learn Java first.

The JDK version I downloaded is 1.6, 32 bit, and the system is Win7.

A default installation, all the way next is OK.

B Environment Configuration

Configure two environment variables: Path,classpath.

Path is the directory where the JDK is installed.

Classpath here for the time being.; (a point is just fine) as to why I studied it again.

If the installation is successful, open cmd, input java-version should be the relevant version of the information such as the occurrence.

3 First program of Java Hello World

 Public class hello{    publicstaticvoid  main (String args[]) {        System.out.println ( "Hello World");}    }

Save the file as Hello.java and put it in E:\gmzJava.

Open cmd, and then click

E: Enter

Gmzjava Javac Hello.java Enter (this step will produce Hello.class, here is the Hello.java source file compiled into Hello.class, similar to the language of human understanding to translate into a machine can read the language)

Java Hello return (performing this step will show Hello world)

Note: The names of the files here are case-sensitive. Java is case-sensitive.

OK next time to study.

D