NOClassDefFound error while running a simple java program

Question

This code is compile fine, but whenever I try to run, it gives an error says NoClassDefFound. What is the possible reason and solution, please explain.

package myPack;

public class PasswordVerification
{
    public boolean verify(String usrId, String pass)
    {
        if(usrId.equals("pranjut")&&pass.equals("password"))
        {
            return true;
        }else
        {
            return false;
        }
    }

    public static void main(String [] main)
    {
         PasswordVerification vp=new PasswordVerification();
         System.out.println(vp.verify("pranjut","password"));
    }

}

I tried both java PasswordVerification and java myPack.PasswordVerification — Cuss
– Cuss, Commented Oct 25, 2009 at 3:09

James Black · Accepted Answer · 2009-10-25 03:06:48Z

1

Are you sure you're calling with the correct package name prefix (i.e "java myPack.PasswordVerification")?

Also, there are some improvements you can make-

Testing a string variable, better to test the constant against the variable- e.g. if ("prajnut".equals(userId) rather than if (userId.equals), as the first form is immune to NullPtrExceptions if you happen to pass in an empty string.
you can simplify by removing the "else" clause -you really only need 1 line

return "prajnut".equals(id)&& "password".equals(pass):

edited Oct 25, 2009 at 3:06

James Black

41.8k10 gold badges92 silver badges172 bronze badges

answered Oct 25, 2009 at 3:05

Steve B.

57.6k12 gold badges99 silver badges134 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

digitaljoel · Accepted Answer · 2009-10-25 03:45:29Z

1

Make sure you are in the directory that contains the myPack folder. You should not be within the myPack folder. I just tried it on my linux machine and it looks like it automatically included the working folder in the classpath, but only if the CLASSPATH environment variable is NOT set. If it is set, then you should either add the current folder to it, or specify the classpath on the command line as follows:

java -cp . myPack.PasswordVerification

edited Oct 25, 2009 at 3:45

answered Oct 25, 2009 at 3:32

digitaljoel

26.6k15 gold badges94 silver badges116 bronze badges

Comments

Nettogrof · Accepted Answer · 2009-10-25 03:24:49Z

0

Be sure that you're at the root project.

if you type "dir" ( windows) or "ls" other Unix-like os, you should see a directory name "myPack".

then type java myPack.PasswordVerification

here some suggestion to code better and respect the Java coding conventions

package myPack;

public class PasswordVerification{


    public boolean verify(String usrId, String pass){
        if("pranjut".equals(usrId) && "password".equals(pass)){
            return true;
        }
        return false;

    }

    public static void main(String[] main){
       PasswordVerification vp=new PasswordVerification();
       System.out.println(vp.verify("pranjut","password"));
    }

}

answered Oct 25, 2009 at 3:24

Nettogrof

2,1362 gold badges15 silver badges22 bronze badges

2 Comments

Cuss Over a year ago

Actually I compiled the code like this javac -d \newfolder\classes PassworedVerification.java, then i go to the director c:\newfolder\classes and then i typed java myPack.PasswordVerification....but it throws NOClassDefFound error.

Nettogrof Over a year ago

like your package is "myPack" you need a directory named "myPack" and place your .class file in it.

Collectives™ on Stack Overflow

NOClassDefFound error while running a simple java program

3 Answers 3

Comments

Comments

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related