Object Oriented Programming in Java

You will be able to understand...

1. Is Java pass by values or pass by reference ?
2. How memory scope does works for methods and members ?

Important Note: Java is pass by value.

What is the output from the following code?

public class Question2 {
   public static void main(String[] args) {
      int a = 5;
      int b = 7;
      swap(a,b);
      System.out.println(a + ", " + b);
   }
   public static void swap(int a, int b) {
      int temp = a;
      a = b;
      b = temp;
   }
}

A) 5, 7

B) 7, 5 //This response is incorrect. Java is pass by value, so the swap method only swaps the parameters a and b, not the original values of a and b in main.

Output: 5, 7

Java Memory Models

key points:

1. main method's scope
2. Constructor's scope
3. The Heap

(what about getter, setter, static, class?)

Example: 1.

2.- What is the output here?

3.

4.

5.

6.

7.