Revision as of 10:01, 4 September 2016

Getting Started

Download and install Java, if you need to.

This will walk through compiling and running a "Hello world" example in Java.

Here's a simple Java "Hello world" program:

public class HelloWorld {
    public static void main(String[] args) { 
        System.out.println("Hello world!");
    }
}

To compile this program, use the javac command:

$ javac HelloWorld.java

This will create a HelloWorld.class file, which is the Java executable.

To run a Java executable, use the java command, and pass it the executable's filename without the extension:

$ java HelloWorld
Hello, world!

@@ Line 39: / Line 39: @@
 Hello, world!
 </pre>
-=File I/O=
-File I/O can be thought of in two parts: the file, and the contents of the file.
-==The File==
-A file can be represented using the '''File''' class. This is a handle to a file, and can be used to either obtain information about the file, or to pass to a file reader or writer to manipulate the file in some way.
 =String Manipulation=