Running Program In UNIX With Package

i have a program in UNIX directory /home/me/java/src

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

I have manage to compile it successfully(class file will be in bin directory) using command below: javac -d /home/t_bmf/java/bin HelloWorld.java

My problem now is how would I execute the class in bin directory in UNIX? I already tried different ways on how to execute it as suggested in my internet research The one I tried is this:

java $CLASSPATH:.:bin/HelloWorld
but I got this error message:
Exception in thread "main" java.lang.NoClassDefFoundError: :/:bin/HelloWorld
Caused by: java.lang.ClassNotFoundException: :.:bin.HelloWorld

[code]....