Variables available only for the class are instance variables

Static variables can be modified by other objects, and accessed throughout the entire class since it is static, is shared by other instances of the same class (e.g s1, s2, etc)

Static methods can call other static methods, you don't have to go through the object to call on the method you can go through the class to call the method

public class Student{
//instance variables 
	private String name;
	private int age;

	private static int totalAge = 0; //class variables

	public void addAgeTotal(int n){ //does not need to return total age because it is a static insstance variable
		totalAge+=n;
	}

	public int getTotalAge(){
		return totalAge;
	}

	public static int getTotalAge(){ // static method 
	}
}

//main class
public class studentMain{
	public static void main(String[]args){
		Student s1 = new Student("Alex", 17); //name, age as parameters
		Student s2 = new Student("Bret", 18);

	//these lines both print out 0 because they can be accessed by both objects from the same class
		System.out.println(s1.getTotalAge());
		System.out.println(s2.getTotalAge());

		s1.addAgeTotal(s1.getAge()); //now age was added to age total, so the method above will print 17
		s2.addAgeTotal(s1.getAge());
	
		//now both lines will display 35
		System.out.println(s1.getTotalAge());
		System.out.println(s2.getTotalAge());

		//now using the class method, we can change s1.getTotalAge()
		System.out.println(Student.getTotalAge());````````
	}
}