Course New Java Syntax - Lecture: Different ways to create variables

"Hi, buddy. I made a copy of your contract for you, just in case. Rishi, that cheapskate, is blissfully ignorant. You should see the figures in my contract. Ha!"

"Good job, Diego. I think I'll learn a lot from you."

"Sure thing, Amigo. There are too many stupid people in the world who want to get rich without actually doing something. But there are even more idiots who are ready to work for free."

"OK, let's get back to our lesson. Now I'm going to teach you several ways to create variables:"

Example	Explanation
`String s1 = new String(); String s2 = "";`	Create two identical empty strings.
`int a;`	Create an `int` variable;
`int a = 5;`	Create an `int`, variable named a and set its value equal to `5`
`int a = 5, b = 6;`	Create an `int`, variable named `a` and set its value equal to `5` Create an `int`, variable named `b` and set its value equal to `6`
`int a = 5, b = a + 1;`	Create an `int` variable named `a` and set its value equal to `5` Create an `int` variable named `b` and set its value equal to `6`
`Date date = new Date();`	Create a Date object. It is initialized to the current date and time.
`boolean isTrue = true;`	Initialize a `boolean` variable to `true`
`boolean isLess = (5 > 6);`	Assign `false` to the `isLess` variable. `Boolean` variables only accept the values true and false.

"Cool, Diego! You always make everything so clear."

"LOL! Thanks, Amigo."

"By the way, I have a couple more exercises for you. How are they going so far?"

"They weren't too hard, and some were pretty funny."

Comments (123)

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Fadhil Radhian Level 18, Semarang, Indonesia

13 March 2023

funny and clear as usual, great article !

Miguel Alonso Ramos Alarcon Level 3, Lima, PERU

16 February 2023

Cat cat9; Cat cat10; Cat cat1 = new Cat(); Cat cat2 = new Cat(); Cat cat3 = new Cat(); Cat cat4 = new Cat(); Cat cat5 = new Cat(); Cat cat6 = new Cat(); Cat cat7 = new Cat(); Cat cat8 = new Cat();

Roman Bortnyk Level 10, Italy

19 April 2022

Hint: The animal.owner can assign woman only after line of the woman obj was created. So you can't assign dog.owner = woman; before the Woman object was created.

Nikita Petrov Level 30, Astrakhan, Russian Federation

20 March 2022

I'm not sure if


String s1 = new String();
String s2 = "";

from the example creates two identical empty strings. "s2" is not filled with any symbols (empty), but "s1" is "null", it's not initialiezed with any string, even empty.

jrcv Level 3, Spain

28 December 2021

aldo en los metodos public estamos declarando la variasbles women y owner por lo que se utiliza public woman owner para cada metodo o objeto dog,fish y cat

Aldo Luna Bueno Level 28, Peru

7 November 2021

Woman woman = new Woman(); cat.owner = woman; Bueno, en estas dos líneas entiendo que pasa lo siguiente. En la primera declaramos la variable woman de tipo Woman, creamos un objeto del mismo tipo, y la variable woman almacena la referencia a este objeto (no el objeto en sí) gracias al operador de asignación (=). En la segunda línea la variable owner de la clase cat, a la cual se accede usando el operador punto con cat.owner, copia la referencia que guarda la variable woman. En conclusión, ahora tenemos dos variables que hacen referencia al mismo objeto, pero el objeto sigue siendo uno solo.

MsebaF Level 10, San Luis, Argentina

24 October 2021

ok, i did understand the excersice but can someone explain this please public static class Cat { public Woman owner; } why is "public Woman owner;" inside the Class cat?

AaronC90 Level 2, Managua, Nicaragua

27 July 2021

hola alguien me puede ayudar con la ultima tarea por favor.

Bak Level 5, Kansas City, United States

16 December 2020

Though I was able to input the right code and pass this problem "pets need people" (task0213), I'm not sure what this means: cat.owner=woman; dog.owner=woman; fish.owner=woman; By writing the above code, are we putting an entire object "woman" into a variable of any given object? Or are we making a reference from a variable (cat.owner) to an object? Thanks.

Mariam Level 9, Columbus, United States

3 September 2020

HINT: You can call it "object" AND you can call it "variable" as well.


Dog dog15;

This variable is "initialized immediately upon creation":


Dog dog48 = new Dog();