Access modifiers in java are used to control the access of other classes to access the class or method.

There are different type of access modifiers used

1.Public-It is the default access modifier it means that your class or method is visible to all other classes and method but in its package.

2.Protected-It can be accessed by any class in its package and by subclass that extends it from another package./

3.Private-It can be accessed in it own class only.

public class Bicycle {

    private int cadence;
    private int gear;
    private int speed;

    // add an instance variable for the object ID
    private int id;

    // add a class variable for the
    // number of Bicycle objects instantiated
    private static int numberOfBicycles = 0;
        ...
}