Running java program in windows cmd. Passing string arg

Question

Hey, this is probably a simple question, but I am having trouble running my java program from command line. I have 3 java files that I compiled and now I have 3 class files in a directory. I want to run them and pass a string parameter to my main.

Code Sample:

package dfa;
public class Main {

public static void main(String[] args) {

    DFA myDFA = new DFA();

    run(myDFA, args);
}

public static void run(DFA myDFA, String[] args)
{
    String test = args[0];
    if(myDFA.accept(test))
        System.out.println("yes");
    else
        System.out.println("no");
}
}

How I am running it:

java -classpath . Main.class testString

Error:

Exception in thread "main" java.lang.NoClassDefFoundError: Main/class
Caused by: java.lang.ClassNotFoundException:Main.class
.
.
.
.
Could not find the main class: Main.class

New Error:

Exception in thread "main" java.lang.NoClassDefFoundError: dfa/class
Caused by: java.lang.ClassNotFoundException:dfa.class
....Could not find the main class: dfa.Main

Post the entire class, please. This will be easy to sort out. — duffymo
– duffymo, Commented Sep 6, 2010 at 19:18

Colin Hebert · Accepted Answer · 2010-09-06 19:39:07Z

5

You shouldn't put the .class extension when your run java.

java -classpath . Main testString is enough if you class is in the default package.

By default, the first non-option argument is the name of the class to be invoked. A fully-qualified class name should be used.

It means that if your class is in a package you have to use java my.package.project.Main

In your case :

java -classpath . dfa.Main testString

To execute this command you must be in the parent folder of dfa directory.

Resources :

edited Sep 6, 2010 at 19:39

answered Sep 6, 2010 at 19:18

Colin Hebert

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6 Comments

casablanca Over a year ago

Rather "you shouldn't put the .class extension".

PFranchise Over a year ago

@Colin Thanks, I was no aware that I had to include the package at the front. However, for some reason I am still having the same issue. Do you know of anything else that might be wrong?

PFranchise Over a year ago

I posted the newest error message. To get this error, I inputted java -classpath . dfa.Main testString

Colin Hebert Over a year ago

To execute this command you must be in the parent folder of dfa directory.

BalusC Over a year ago

..and thus not inside the dfa folder or somewhere else.

|

duffymo · Accepted Answer · 2010-09-06 19:24:13Z

2

Try this:

java -classpath . dfa.Main testString

The name of your class must be the fully resolved class name, including the package.

answered Sep 6, 2010 at 19:24

duffymo

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