I'm fairly new to working with packages in java but I've got a file structure thats:

* project  

	+ classes  

		- src  

			* com  

				+ main  

					- Billing.class
					- Password.class
	+ src  

		- com  

			* main  

				+ Billing.java
				+ Password.java

Each java file has package `package src.com.main;` at the top.
I'm compiling from the project folder using `javac -d ./classes/ ./src/com/main/*.java` and it compiles fine. When I go to run it using `java classes/src/com/main/Billing` is gives me a NoClassDefFound exception. What am I doing wrong?

Edit: Entire Error:  

`java classes/src/com/main/BillingException in thread "main" java.lang.NoClassDefFoundError: classes/src/com/main/Billing (wrong name: src/com/main/Billing)
 at java.lang.ClassLoader.defineClass1(Native Method)
 at java.lang.ClassLoader.defineClass(ClassLoader.java:800)
 at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
 at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
 at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
 at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
 at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
 at java.security.AccessController.doPrivileged(Native Method)
 at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
 at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
 at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
 at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
 at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:482)`