CodeGym /Java Course /Java Core /Useful links from the Professor — 12

Useful links from the Professor — 12

Java Core
Level 2 , Lesson 10
Available

"Well, hello, Amigo! Good news! I'm wrapping up work on a super accurate predictor!"

"Cool. What does it do? Will it predict when I'll become a cool programmer?"

"Hey, don't rush, my young robot! I didn't look that far ahead, but I already know that…"

"What?!"

"…I saw that you would come to me with questions about the topics you studied this week. So, I prepared additional materials for you in advance: they'll help you figure everything out."

How to use polymorphism

"Polymorphism's main advantage is flexibility. On the one hand, you can work with multiple data types as if they were the same type. On the other hand, you can still preserve objects' specialized behavior. When do you need to cast to a common type and when do you need specific characteristics? We'll talk about this.

How method overriding works

You're already familiar with method overloading. It's time to learn about overriding classes. This will help you when you need a common method to perform different actions depending on the class it is called in. Everything is possible! The important thing is to know how :)

Why interfaces are necessary in Java

This lesson provides a relaxed and detailed description of what interfaces are and why they appeared in the language. And you'll learn about popular Java interfaces. Prepare yourself! This topic has a sequel!

Default methods in interfaces

Every version of Java differs from those that came before. Version eight introduced the concept of default methods in interfaces. This lets you define default methods and implement them inside an interface. You'll find examples and explanations in this lesson.

Specific examples of abstract classes in Java

You've become acquainted with abstract classes. You already know that they're like 'blanks' for your future classes. But do all methods of such a class have to be abstract? And why doesn't Java have multiple inheritance? Here's a 'tip' from my super accurate predictor: the material from this lesson will better prepare you for the next level.

Comments (12)
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Kristian Kelij Level 18, Slovakia
16 January 2023
Does anybody have a problems with DM (Dark Matters) ? I've saved around 200 DM in Java AP Lite course and now I have roughly 30 ... I've completed almost all tasks ...
Hiyo Level 24
2 February 2023
Do you have premium? I ran out of DM early on so I bought premium for 1 month during sales to get the premium tasks, now I have over 2k+ DM. Another way you can get DM is by redoing the surveys but it's very slow...
Lawson Level 29, Lagos, Nigeria
24 August 2020
Pls can a class inherit a parent class and an interface at the same time and how please
Agent Smith Level 38
24 August 2020

public class Class2 extends Class1 implements ExampleInterface {
    //
}
P.B.Kalyan Krishna Level 24, Guntur, India
6 April 2022
"extends" first and then "implements". First extend the base class and then implement the interfaces. It must be in that order.
Randall John Level 19, San Jose, United States
2 June 2020
im afraid of running out of dark matter o.o
Angel Li Level 18, Fremont, United States
29 June 2020
Same! I had 400+ when I was completing Java Syntax then after this I'm down to 289 😅 I think there should be more tasks or something so we can get more dark matter, but I think I have enough for now.
Oliver Heintz Level 18, Mustang, United States
28 November 2020
I have 355 right now. I haven't skipped anything. Did you skip tasks in the past?
Ahmad Level 23, Riyadh, Saudi Arabia
28 December 2019
do not immerse your self in reading and forget to practice :)
MaGaby2280 Level 41, Guatemala City, Guatemala
21 November 2019
Great links... really good extra information about these topics!!!
Ramilya Level 20, SPb, Russian Federation
14 March 2019
/* The comment was deleted */
26 July 2019
intriguing...