Java NoClassDefFoundError with inherited class -

i've started learning java i'm having few problems related noclassdeffounderror. i've tried research solutions site , elsewhere still haven't been able solve them. run programs windows 7 command prompt classpath environment variable set instead of defining each program run. it's set c:. troubleshoot, created test package simplified directory structure.

in c:\test, have shape.java , circle.java. shape.java looks this:

package test;  class shape {     void draw() { system.out.println("drawing new shape"); } } 

and circle.java looks this:

package test;  public class circle extends shape {         public static void main(string[] args) {         circle round = new circle();         round.draw();     } } 

if compile both shape.java , circle.java c:\ in command prompt operations like

c:\>javac test\shape.java  c:\>javac test\circle.java 

and run compiled circle.class file like

c:\java test\circle 

i output expect:

drawing new shape 

however, if compile shape.java , circle.java inside c:\test like

c:\test>javac shape.java  c:\test>javac circle.java 

and try run circle.class anywhere like

c:\test>java circle 

or this

c:\> java test\circle 

i following error message.

exception in thread "main" java.lang.noclassdeffounderror: circle (wrong name: t est/circle)         @ java.lang.classloader.defineclass1(native method)         @ java.lang.classloader.defineclass(classloader.java:792)         @ java.security.secureclassloader.defineclass(secureclassloader.java:14 2)         @ java.net.urlclassloader.defineclass(urlclassloader.java:449)         @ java.net.urlclassloader.access$100(urlclassloader.java:71)         @ java.net.urlclassloader$1.run(urlclassloader.java:361)         @ java.net.urlclassloader$1.run(urlclassloader.java:355)         @ java.security.accesscontroller.doprivileged(native method)         @ java.net.urlclassloader.findclass(urlclassloader.java:354)         @ java.lang.classloader.loadclass(classloader.java:424)         @ sun.misc.launcher$appclassloader.loadclass(launcher.java:308)         @ java.lang.classloader.loadclass(classloader.java:357)         @ sun.launcher.launcherhelper.checkandloadmain(launcherhelper.java:482) 

could explain why java files compile within c:\test folder compiled circle file produces error? there wrong classpath? reading , forthcoming solutions!

edit: i've done bit more testing , turns out if compile shape.java , circle.java files c:\test directory run c:\ directory, works. change anything?

edit 2: after more testing, turns out can in fact compile , run shape.java , circle.java files within c:\test directory long use command java test.circle. misunderstood way in jvm looks classes. understand uses same method compiler when analyses package import statements.

you can anywhere on system, long have classpath bounded in .

only java vm able scan classpath, , locate class test.circle in package test.

so, correct execution java test.circle (always), , classpath needs point have \test\circle.class available. check circle.class expect it.