Exception in thread "main" java.lang.NoClassDefFoundError:

[Amith Bhavikatti]

Hi All,

i am tring to run a java program from commandline .
i included all classpaths while compiling the java file.
i included all environment variables.

i compiled it and i got the generated class file.
but still i cannot run the program.

This is the command and the error which i am getting:

E:\ECost>java MyProgram
Exception in thread "main" java.lang.NoClassDefFoundError: MyProgram (wrong name
: ECost/MyProgram)
at java.lang.ClassLoader.defineClass0(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.access$100(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)


Please help me.
Thanks in Advance

[Campbell Ritchie]

Please supply more details.

Where is the MyProgram.class file? (Not a good name, by the way: the class name ought to make it obvious what the class is all about).

Have you got it in the folder you are using at present (use the "dir" instruction from the command-line on Windows to find it)?

Have you got a package declaration in MyProgram?

Have you set up a system or user CLASSPATH as a permanent environment variable (which is usually a mistake, despite what people tell you)?

[Jesper de Jong]

E:\ECost>java MyProgram
Exception in thread "main" java.lang.NoClassDefFoundError: MyProgram (wrong name: ECost/MyProgram)

This suggests that your class MyProgram has a package statement:

package ECost;

You're calling it the wrong way. Make sure that the base directory of the package in in the classpath, and specify the fully qualified name of the class (i.e. the package name, dot, class name) on the command line:

E:\>java ECost.MyProgram

or:

C:\Somewhere>java -classpath E:\ ECost.MyProgram

(note the space between E:\ and ECost.MyProgram).

[j srinivas]

Well the exception occurs when your compiler tries to execute the class file.
i assume your CLASS PATH variable and JAVA_HOME are not properly set.
while setting class path include . also,because . specific to include current directory.

If that is not the case,then type directory in your command prompt and try to find your file,i bet .class file would be missing.That means your working in wrong directory.



Keep it simple not simpler.