Example: You have a class named "Set" in a project folder "e:\myProject" and package named com.zxy.client, will you be able to compile and execute it as it is
package com.xyz.client;
public class Pet {
public static void main(String[] args) {
System.out.println("I am found in the classpath");
}
}
To run-> e:\myProject> java com.zxy.client.Set
The answer is no and you would get the following exception: "Exception in thread "main" java.lang.- NoClassDefFoundError: com/zxy/client/Set". You have to set the classpath. How shall you do that? One of the following ways:
1. Set the operating system CLASSPATH environment variable to have the project folder "e:\myProject".
2. Set the operating system CLASSPATH environment variable to have a jar file "e:/myProject/client.jar", which has the Set.class file in it.
3. Run it with -classpath or -cp option as given below:
c:\>java -cp c:/myProject com.xyz.client.Pet
OR
c:\>java -classpath c:/myProject/client.jar com.xyz.client.Pet