Running the java class in the terminal failing

Question

I tried to run my java class generated using netbeans 10.0 in terminal as below:

 ~/Desktop/JavaLesson5/build/classes/javalesson5$ java javalesson5.JavaLesson5

but I keep getting the error below:

Error: Could not find or load main class javalesson5.JavaLesson5
Caused by: java.lang.ClassNotFoundException: javalesson5.JavaLesson5

My java code is as below:

package javalesson5;
import java.util.*;
import java.io.*;

public class JavaLesson5{

    public static double myPI = 3.14159; //Class variable

    public static int addThem(int a, int b){
      double smallPI = 3.140;//Local variable
      System.out.println("Local "+myPI);

      int c = a + b;
      return c;
    }


    public static void main(String[] args) {
      System.out.println(addThem(1,2));
    }

}

I think you are running your program within pacakge.so just write "java JavaLesson5". — Sanjay, Feb 23 '19 at 04:13
@Sanjay nope, that doesn't work. In theory Java could try to work out the classpath based on (a) the current directory and (b) the package of the main class. But it would only be useful in a small number of cases and probably not worth the effort of explaining how it works. — Willis Blackburn, Feb 23 '19 at 04:23

Willis Blackburn · Accepted Answer · 2019-02-23T04:13:29.840

0

Try:

java -cp ~/Desktop/JavaLesson5/build/classes javalesson5.JavaLesson5

You use classes as the classpath because you've specified javalesson5 as part of the classname. For each directory in the classpath (just one in this example) Java will look for a directory called javalesson5 and then look for the JavaLesson5 class in that directory.

edited Feb 23 '19 at 04:13

answered Feb 23 '19 at 03:59

Willis Blackburn

8,068
19
36

I had earlier tried it in its folder but it had still failed. Does that mean that the approach of java javalesson5.JavaLesson5 is totally wrong and should not be used? – Feb 23 '19 at 04:09
1

You always have to set the classpath either by specifying `-cp` or setting the environment variable `CLASSPATH`. If you set `CLASSPATH` to `~/Desktop/JavaLesson5/build/classes` then you can run `java javalesson5.JavaLesson5` without specifying `-cp`. – Willis Blackburn Feb 23 '19 at 04:15
I now understand the whole concept. Thank you – Feb 23 '19 at 04:24

Running the java class in the terminal failing

1 Answers1