Using advanced principles of object-oriented programming, Polymorphism ,Inheritance, interfaces and abstract classes, correct division into files, documentation, Efficiency use of constants, readable names, Files Read/Write, multithreading , and more.
The vehicle agency project maintains a pool of various vehicles with options to Add, Buy, testDrive, and more.
Polymorphism ,Inheritance, interfaces and abstract classes, correct division into files, documentation, Efficiency use of constants: An abstract Main Vehicle class with general attributes. 3 abstract classes that extend the main class: Marine vehicles, Air vehicles and Land vehicles. And the Vehicle Classes: Jeep, Frigate, SpyGlider, ToyGlider, Amphibious, Bicycle, CruiseShip. A Vehicle can be motorized or not motorized {interface}. A Vehicle has a means of transportation (typeOfLicense of MINI/LIMIT/UNLIMITED) {interface}. the above hierarchy within the package of transport tools. Note that means of transportation is an abstract class. Motorized or non-motorized is behavior and are implemented as interfaces And as above commercial implemented as an interface. Functionality of the JFrame menus and JButtons
multithreading for better performance. more Functionality options for the user. And more.

