Question

I created one java file then i converted into jar now i want to use it in another java class how to import that jar and how to compile and execute.

Answer 1

Given a “library” class pkg/LibClass.java:

package pkg;

public class LibClass {
    public static void sayHello() {
        System.out.println("Hello world");
    }
}

Compile and create a jar file:

$ javac pkg/LibClass.java 
$ jar cvf lib.jar pkg/LibClass.class
added manifest
adding: pkg/LibClass.class(in = 404) (out= 284)(deflated 29%)

(creates a lib.jar in the current directory)

Create an application that uses the library:

import pkg.LibClass;

public class MainClass {
    public static void main(String[] args) {
        LibClass.sayHello();
    }
}

Compile and run the application using lib.jar:

$ javac -cp lib.jar MainClass.java 
$ java -cp lib.jar:. MainClass