My java compiler is not finding the hello world.java file that i have saved on my desktop. I've done research and most posts say something about setting my environmental variables such as PATH and CLASSPATH. Could someone please explain to me how to do this and give me good beginner definitions of what these two variables are and why they are important to the compiler? I am using a macbook pro and my text editor is bbedit. I have tried the helloworld program in two text editors including this one and i get the same result in terminal. Thanks for the help.