Overlapping classes under the same package in java

Question

I am learning Java on my own, i came a cross this interesting example and i found it difficult to understand it.

What i want to know is, what is this called in Java when you have several classes under the same package all of them are Overlapping. Please take a look at the example below ? Note that none of the classes use implements, interface, abstract, extends etc...

And is it possible to find more of these examples ?

class Flightplan

public class Flightplan {
    String type;
    int seat;
    String from;
    String to;
         // Other local variables, style captain ...
    Person[] passenger;
    int counter = 0;

    Flightplan (String t, int s, String startPlace, String d) {
        type = t;
        seat = s;
        passenger = new Person [s-1]; // kapten tar ett säte 
          // Captain takes a seat
        from = startPlace;
        to = d;
    }

    void book (Person p, String f, String t) {
        if (f.equals(from) && t.equals(to)) {
            passenger[counter] = p;
            to = t;
            counter++;
        }
                else System.out.println(p.name + " try to book a wrong flight !");
    }

    void flyg() {
        System.out.println("On the plane " + this.typ + " reser"); 
        for (int i = 0; i < passenger.length && passenger[i] != null; i++) {
            System.out.println(passenger[i].name + ", ");
        }
        System.out.println("\n");
        from = to;
    }

}

class Person

public class Person {
    String name;
    String from;
    String to;
    String stopover;
    int bags;
    Flightplan flight;

    Person (String n, String f, String m, String t, int v) {
        name = n;
        from = f;
        stopover = m; // Only one stopover is approved, otherwise we would enter this as an array
        to = t;
        bags = v;
    }

    void boardNextLeg(Flightplan plan) {
        flight = plan;

// Function bar for a stopover due. if-kit building
        if (!stopover.equals(null) && flight.from.equals(this.from) && flight.to.equals(this.stopover)) { 
            System.out.print(this.name + " is now in between");
            System.out.println(from + " and " + stopover);
            flight.book(this, from, stopover);
        }
        else if (flight.from.equals(this.from) && flight.to.equals(this.to)) {
            System.out.println(from + " och " + to);
            flight.book(this, from, to);
        }

                else System.out.println(this.name + " could not be booked on a flight");
    }


}

score 0 · Answer 1 · answered Nov 26 '16 at 19:39

By overlapping you mean that they have member variables with the same names? Each class has a different list of member variables, and one class presents no restrictions to another class.

I think this is called "Several classes that each deal with similar data values"

score 0 · Accepted Answer · edited May 23 '17 at 12:24

What is this called in Java when you have several classes under the same package all of them are Overlapping ?

This is NOT overlapping, rather this is called circular dependency because your Flightplan and Person are dependent on each other, which is bad design and poorly developed.

Basically Circular Dependencies cause lots of issues (like OutofMemoryError) if not properly used, so they should be avoided in between the classes/packages.

You can look here for more details on circular dependencies.

Overlapping classes under the same package in java

2 Answers2