non static method cannot be referenced from static context [duplicate]

Answer 1

The method journeyCost is non-static; so it's an instance method and it requires an instance of Journey to get executed. The sentence Journey.journeyCost(thisJourney); is invoking the method in a static way, and its expecting that your method is a class-level method (or static).

So, you can make your journeyCost method static for your call to work:

public static boolean journey(int date, int time, int busNumber, int journeyType)

Or try invoking the method from a proper instance:

Journey aJourneyInstance = new Journey();
thisJourney.costOfJourney = aJourneyInstance.journeyCost(thisJourney);