Java Basics Using Qt Jambi Tutorial

Packages

Packages is used to group related types which are classes, interfaces, enumerations and annotation types.

Ex.

//in UseCar.java

package com.cars.engine;

public interface UseCar{}

//in Vehicle.java

package com.cars.engine;

public abstract class Vehicle{}

3 Ways to access members:

1. Full qualified name. Ex. com.cars.engine.Vehicle;

2. Import package member. Ex. Vehicle v1= new Vehicle();

3. Import members entire package.

Ex.

import com.cars.engine.*;

Vehicle v1 = new Vehicle();

Car car1 = new Car();

Things you must remember with packages:

1. You must name packages with correct convention to make it unique and avoid name clashes.

Ex. package com.cars.engine;

2. Your class files should be located in the directories with names using the package name.

$javac -classpath /path/to/jar:/path/to/jar -d /path/to/folder/containing/java/files/ MyCar.java Vehicle.java $jar cfm MyCar.jar Manifest.txt /com/cars/engine/*.class $java -jar Main.jar

to be continued...