Class path magic

[Amu mathi]

Hello,

Iam trying Hello world program in windows enviroment, I use the default package for running this program so it works fine in the following command

such as java -cp . Hello

If i use a package such as com.college.learn

Then I compile the file using command javac -d Hello.java it creates a folder structure as com\college\learn and places a class file Hello in that folder

Now to execute that class file from the base folder ie c:

I use the following command java -cp . com.college.learn.Hello

But when I try to run the same command from the folder cd com\college\learn I get a error stack.

Can anyone tell me how can i execute the program from the the folder com\college\learn

[Rakesh Chaudhary]

hi

Keep the Base folder selected in the Editor you are using .and run using the basic command java File name without extension i.e(.java)..

Hope this helps

[Sagar Rohankar]

java -cp . com.college.learn.Hello

When you are in same directory as that of package , no need to give package name , just type "java Hello" ..

[Amu mathi]

Thanks for the inputs

In the same folder ie com\college\learn when I try running

c:\ cd com\college\learn

Then type

Java Hello

I get the following error

Exception in thread "main" java.lang.NoClassDefFoundError: Hello (wrong name: com/college/learn/Hello)
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)

[Sagar Rohankar]

Sorry for the mistake ..

This help.

java -cp ../../.. com.college.learn.Hello

[Campbell Ritchie]

Welcome to JavaRanch.

If you have a package declaration in the class file, execute it from the "root" folder with java com.college.learn.Hello

You can miss out the "-cp ." You are not supposed to run it from the included folders.

[Amu mathi]

Thanks Campbell,

I got my answer; so it is illegal and not allowed in Java.

[Campbell Ritchie]

Originally posted by Amu mathi:
Thanks Campbell,

I got my answer; so it is illegal and not allowed in Java.

You're welcome. I don't know whether it is actually "illegal;" you would have to look through the specifications for the java.exe program to find that out. But it never seems to work when I try it!