Thread: Main Class not loading

Hey guys, literally just started trying to learn Java and already running into trouble-
Version Info-
C:\Program Files (x86)\Java\jre7\bin>java -version
java version "1.7.0_21"
Java(TM) SE Runtime Environment (build 1.7.0_21-b11)
Java HotSpot(TM) Client VM (build 23.21-b01, mixed mode, sharing)

Just trying a little 'Hello World' and I keep getting this error: "Error: Could not find or load main class C:\Java\hello2.java"

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

A class like Hello that is designed to be "run" with a main() is normally made public. Ie, is declared as "public class Hello { etc".

More importantly it must in a file Hello.java. The file name and class name must match: this is part of Java's way of identifying classes at runtime.

Still the same:

C:\Program Files (x86)\Java\jre7\bin>java C:\Java\Hello.java
Error: Could not find or load main class C:\Java\Hello.java

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

You have to first compile, then run. The compiler executable is javac.exe: it turns your .java file into a binary class file. Then you use the java.exe executable to actually run the file.

The commands are

javac -cp . Hello.java
java -cp . Hello

Notice how javac expects the name of a file (to compile) while java expects the name of a class (with no extension, to run).

The dash-c-p-space-dot business is a common way of specifying the classpath. The classpath is the place Java expects to find class files.

---

Step by step instructions for compiling and running a hello world program can be found in the "Hello World!" for Microsoft Windows page of Oracle's Tutorial.

Got it now, I had the wrong version or type of Java installed *facepalm*, thanks mate.