/**

* Demonstrates uses of objects and wrappers.

*/

public class Objects {

public static void main(String[] args) {

// primitives vs objects

int number = -2;

char symbol = '!';

char[] array = {'c', 'a', 't'};

String word = "dog";

String word1 = new String("dog"); // creates a string object

String word2 = "dog"; // implicitly creates a string object

// the null keyword

String name0 = null;

int[] combo = null;

// System.out.println(name0.length()); // NullPointerException

// System.out.println(combo[0]); // NullPointerException

// Strings are immutable

String name = "Alan Turing";

String upperName = name.toUpperCase();

name.toUpperCase(); // ignores the return value

System.out.println(name);

name = name.toUpperCase(); // references the new string

System.out.println(name);

String text = "Computer Science is fun!";

text = text.replace("Computer Science", "CS");

// Wrapper classes

Integer i = Integer.valueOf(5);

System.out.println(i.equals(5)); // displays true

Integer x = Integer.valueOf(123);

Integer y = Integer.valueOf(123);

if (x == y) { // false

System.out.println("x and y are the same object");

}

if (x.equals(y)) { // true

System.out.println("x and y have the same value");

}

String str = "12345";

int num = Integer.parseInt(str);

num = 12345;

str = Integer.toString(num);

}

}