I have to implement a program in Java where there is an object list with cars. For each car i have the manufacturer, the model and its cost. My program should read the list and show how many different models are from the same manufacturer. Every double log will be ignored. The implementation should be with hashmap, Set and JOptionPane. Example of the list and the print :

list

Toyota Yaris 14000

Opel Corsa 16000

Toyota Aygo 11000

Toyota Corolla 17000

Fiat Panda 12000

Opel Corsa 15500

Toyota Yaris 17000

Opel Astra 19000

Fiat Tipo 12000

print

Fiat: 2 [Panda, Tipo)

Opel: 2 [Corsa, Astra]

Toyota: 3 [Yaris, Aygo, Corolla]