How to use classes from .jar files?

Let’s say we need to use the class Classname that is contained in the jar file org.example.jar

And your source is in the file mysource.java Like this:

import org.example.Classname;

public class mysource {
    public static void main(String[] argv) {
    ......
   }
}

First, as you see, in your code you have to import the classes. To do that you need import org.example.Classname;

Second, when you compile the source, you have to reference the jar file.

Please note the difference in using : and ; while compiling

If you are under a unix like operating system:
```
javac -cp '.:org.example.jar' mysource.java
```

If you are under windows:

javac -cp .;org.example.jar mysource.java

After this, you obtain the bytecode file mysource.class

Now you can run this :

If you are under a unix like operating system:
```
java -cp '.:org.example.jar' mysource
```
If you are under windows:
```
java -cp .;org.example.jar mysource
```