Home/ Questions/Q 8941271
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-06-15T11:15:42+00:00

My directory structure is like this: > makefile > app.jar > src > Main.java

  • 0

My directory structure is like this:

> makefile
> app.jar
> src
    > Main.java
    > Main.class
    > some other classes
    > manifest.txt

I compile from the makefile with these commands:

javac src/*.java
jar cvfm app.jar src/manifest.txt src/*.class

manifest.txt contains this:

Main-Class: Main

When I run java -jar app.jar from the top directory I get this error:

$ java -jar app.jar 
Exception in thread "main" java.lang.NoClassDefFoundError: Main
Caused by: java.lang.ClassNotFoundException: Main
    at java.net.URLClassLoader$1.run(URLClassLoader.java:217)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
Could not find the main class: Main. Program will exit.

I tried changing the manifest to say Main-Class: src.Main but that didn’t work either. This is probably very simple but I’m finding Google doesn’t provide any simple solutions.

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    Please find the answer from Oracle

    http://docs.oracle.com/javase/tutorial/deployment/jar/build.html

    Please find the sample code:-

    package oata
public class HelloWorld {
 public static void main(String[] args) {
    System.out.println("Hello World");
 }
 }

    Create a folder to place the .class file
    Then compile the and run the file.

     `md build\classes
   javac -sourcepath src -d build\classes src\oata\HelloWorld.java
  java -cp build\classes oata.HelloWorld`


  `echo Main-Class: oata.HelloWorld>myManifest
     md build\jar
    jar cfm build\jar\HelloWorld.jar myManifest -C build\classes .
    java -jar build\jar\HelloWorld.jar`

    Thanks
    Pavan

    • 0