Need a little help here

Question

Hey everyone, I am brand new to JAVA and have hit a road block. It is my understanding that some information has to be added into the Environment variables.
This is what I have so far.
JAVA_HOME
c:\Program Files\Java\jdk1.7.0
Path
%JAVA_HOME%\bin;
CLASSPATH
.;%JAVA_HOME%\lib
The program I created will compile in the command prompt window and I get no errors however when I run it I get "Error: Could not find or load main class javacheckout.java
The .class file and the .java file are named the same and reside in the same folder.
Any help would be great.

Answer 1

JAVA_HOME: Not needed in general. May be used by some tools, but even then it may not be necessary, just one place where they look for things.
PATH: Yes, you'll want to add Java's bin directory to this variable, so that you can just type "java", "javac", etc., without having to provide the full path every time.
CLASSPATH: Don't use this. Better to use -cp or -classpath on the command line. Whether you use CLASSPATH or -cp/-claspath, it should NOT include anything under the Java installation directory. That stuff will be found automatically relative to the executable.
If your class is name MyClass, and is not in any package (you did not inlcude a "package" statement at the top of MyClass.java), then you would do
java -cp directory_containing_MyClass.class MyClassFor instance, if MyClass.class is in C:/projects, then you could do
java -cp C:/projects MyClassOr, if you're already in C:/projects in your terminal window, then you can do the above or simply
java -cp . MyClassIf MyClass is in a package (e.g., MyClass.java starts with package com.a.b;) then somewhere you'd need a directory subtree whatever/com/a/b/MyClass.class. So say you have C:/projects/com/a/b/MyClass.class, then you'd do
java -cp C:/projects com.a.b.MyClassNote that you cannot do something like
java -cp C:/projects/com/a/b MyClassThe class name given to the command line MUST be the fully qualified class name, including the full package name if present, and the first element of the package structure must be directly inside a classpath element ("com" must be directly inside "C:/projects").