I'm very new to Java and want to be difference between class variables and instance variables.

For example:

    class Bicycle { 
        int cadence = 0; 
        int speed = 0; 
        int gear = 1; 
    }

How are instance variables and class variables are different from each other?

I'm also having trouble understanding how several instance variables can be different from each other and yet come from the same class variable.