Using java to run java files Problem

[Mohit G Gupta]

i have a file MyClass.java in pack/sample1

it contains:

  package pack.sample1;
import java.util.*;

public class MyClass     {

public static void main(String args[]){


Properties p=System.getProperties();
p.setProperty("Name","myMohit");
p.list(System.out);
                          }

}
  

i am in sample1 directory

javac MyClass.java

complies fine

but when i run the file

java MyClass

i get the following error:



C:\Users\mohit\DOCUME~1\Javafiles\pack\sample1>java MyClass
Exception in thread "main" java.lang.NoClassDefFoundError: MyClass (wrong name:
pack/sample1/MyClass)
at java.lang.ClassLoader.defineClass1(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$000(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)
Could not find the main class: MyClass. Program will exit.


if i run using java pack.sample1.MyClass
then also the error appears

C:\Users\mohit\DOCUME~1\JAVAFI~1\pack\sample1>java pack.sample1.MyClass
Exception in thread "main" java.lang.NoClassDefFoundError: pack/sample1/MyClass
Caused by: java.lang.ClassNotFoundException: pack.sample1.MyClass
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)
Could not find the main class: pack.sample1.MyClass. Program will exit.

[Sumit Khurana]

when you are running
java pack.sample1.MyClass1

than you must be in the directory above the pack

[Mohit G Gupta]

what about..



C:\Users\mohit\DOCUME~1\Javafiles\pack\sample1>java MyClass

it too give error



As sumit saidd

when you are running
java pack.sample1.MyClass1

than you must be in the directory above the pack

why you must be in the directory above the pack???

[Wouter Oet]

Because that's how it is defined. Is a class is in a package it must be called from the parent directory of the package directory.

[Trivikram Kamat]

mohitkumar gupta wrote:
if i run using java pack.sample1.MyClass
then also the error appears

C:\Users\mohit\DOCUME~1\JAVAFI~1\pack\sample1>java pack.sample1.MyClass
Exception in thread "main" java.lang.NoClassDefFoundError: pack/sample1/MyClass
Caused by: java.lang.ClassNotFoundException: pack.sample1.MyClass
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)
Could not find the main class: pack.sample1.MyClass. Program will exit.

Sumit Khurana wrote:
when you are running
java pack.sample1.MyClass1

than you must be in the directory above the pack

Consider you have file Test.java with following package:

package pack1.subpack1;

Then in order to run the code after compiling, you need to cd to folder containing pack1 and run following command

java pack1.subpack1.Test