CodeGym /Courses /Java Syntax /Useful Links from the Professor – 10

Useful Links from the Professor – 10

Java Syntax
Level 10 , Lesson 9
Available

"Well, Amigo, are you ready for the Java Core quest?"

"I'm not sure. What do I need to do?"

"You need to get through the tenth level, of course! And not 'as soon as possible', but 'as well as possible'! Don't rush. Learn the theory and then complete the tasks. Here are some useful articles on the subject matter."

"I'm a little confused about widening/narrowing... It seems like a simple topic, but…"

"That's normal! Our wonderful articles will help you. And not just with widening and narrowing."

Widening and narrowing of primitive types

"To start, let's re-read about widening and narrowing of primitive types (those types that are not objects). This is the simplest thing, but can be forgotten quickly without practice. So, let's read and practice."

Fixed values in Java: final, constants, and immutable

"Everything flows and changes in Java... except things marked with the final modifier (i.e. marked as CONSTANT). Do you already know why that word is written in uppercase letters? If not, this article will tell you why. You'll also learn why the state of some objects can't be changed, and how to use this property."

instanceof and Inheritance 101

"What belongs to who, and who's related to what? In Java, things aren't quite like they are in life: if you're higher in the hierarchy, then everything belongs to you, and if you are lower in the hierarchy... Don't know what I'm talking about? Yep, about inheritance... And about the very, very useful instanceof operator. I strongly recommend that you start using it in your programs!"

Wrappers, unboxing, and boxing

"Since you have a good grasp on primitive types, you should read more about wrapper classes. These are classes that look and act like their similarly named primitive types, but they are, in fact, real classes. In this article, you'll learn who needs them and why, and how to use them. "

How to use the Enum class

"You already know how to create classes. But what would you do if you needed to limit a range of values in your class? Until the release of Java 1.5, developers had no choice but to come up with their own solutions to this problem. The Enum class was introduced in the release to provide a common solution. It has quite a few capabilities along with some peculiarities. This article will teach you more about how Enum differs from other classes."

8 common mistakes made by rookie programmers

"Both beginners and experienced programmers make mistakes. By the end of the first quest, I think you'll benefit from reading about the common fall traps. Let's revisit the most important rules."

10
Task
New Java Syntax, level 10, lesson 9
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The whole duck isn't enough
Using the Duck class as a pattern, create Cat and Dog classes. What do you think the toString method in the Cat and Dog classes should return? In the main method, create two objects of each class and display them on the screen. Duck objects have already been created and are displayed on the screen.
10
Task
New Java Syntax, level 10, lesson 9
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Man and woman
1. Inside the Solution class, create public static Man and Woman classes. 2. The classes must have the following fields: String name, int age, String address. 3. Make constructors that have all possible parameters. 4. Create two objects of each class with complete data using a constructor. 5. Displa
10
Task
New Java Syntax, level 10, lesson 9
Locked
Dog registration
The Dog class must have three constructors: - Name - Name, height - Name, height, color.
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Task
New Java Syntax, level 10, lesson 9
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Tom and Jerry
Create Dog, Cat, and Mouse classes. Add three fields of your choice to each class. Create objects for the characters in the cartoon "Tom and Jerry". You'll recall there are quite a few. For example: Mouse jerryMouse = new Mouse("Jerry", 5, 2), where 5 is the height in inches, and 2 is the length of
10
Task
New Java Syntax, level 10, lesson 9
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Display today's date
Display the current date in the following format: "06 15 2018".
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Task
New Java Syntax, level 10, lesson 9
Locked
Number of words in a string
Implement the getWordCount(String) method to return the number of words in the string received in the input parameter. Hint: A word is a sequence of non-whitespace characters separated by a single space.
10
Task
New Java Syntax, level 10, lesson 9
Locked
Binary encoding
Since computers only operate using 0s (no voltage) and 1s (voltage), there is a need to translate human-readable data into machine-readable data. Digits, symbols and special characters have their own code (decimal number) in the Unicode table. Implement the toBinary(int) method, which converts the d
10
Task
New Java Syntax, level 10, lesson 9
Locked
IPv6
In the map method, parse a string representing the IPv6 address and return the result as an array of strings. For example, for the input string "2001:db8:11a3:9d7:1f34:8a2e:7a0:765d", you need to get an array like this: [2001, db8, 11a3, 9d7, 1f34, 8a2e, 7a0, 765d] Use a StringTokenizer to parse th
Comments (12)
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ImDevin Level 15, Old Town, United States
17 May 2021
Whoa, soo much information!
Agent Smith Level 38
22 August 2020
Make sure to check other articles in other CodeGym groups - there is a ton of useful information there. Actually, only a few of them are mentioned in lessons, so it is up to you to explore!
Vitalina Level 20, Poland
25 October 2020
Thank you!
Clint Level 22, cincinnati, united states
22 November 2020
it really shouldnt be
Nikitata Level 22, Ba Sing Se, United States
14 July 2020
Honestly, these articles are the best part of the course.
Austeja Level 10, Kaunas, Lithuania
22 May 2020
Really recomrmending to read all the articles carefully. It helped me to sum up the knowledge from all the 10 Syntax levels.
MaGaby2280 Level 41, Guatemala City, Guatemala
11 November 2019
These links are really useful!!!
Alexandru Ovcinicov Level 15, London, United Kingdom
15 September 2019
That reading took me some time, but reading them all till the end, i find myself more confident in understanding Java concepts and i found my weak spots, as for example : i forgot/didn't remember that when we do: (a == i++) => a==i is done first, then i++. And i refreshed my knowledge of Strings Objects and their major use in Java, the big part pf lessons was related to how to make value comparisons correctly == & Object.Equal(). About passing values to methods by references or by values (not sure about tautology rules here) About Immutability of wrapper classes like String , Integer , StackTrace... About Inheritance & etends(i write it all from memory now, means that maybe i will remember this for a bit longer))), Enums and so on ... My fingers eager to code now, Let's go!
Nikolaos Level 22, Vrontados, Greece
5 September 2019
Enum looks really handy.
Renat Mukhametshin Level 16, Pervouralsk, Russain Federation
8 August 2019
cool!
Hashirama Level 26, Port-Harcourt, Nigeria
1 February 2019
True. They are indeed useful links...!!!
Thang Za Thang Level 18, Melbourne, Australia
5 July 2020
After the devastating events of the fourth great ninja war, first Hokage Hashirama Senju has found a way to override Orichimaru's Reanimation Jutsu and has lived through the events of Boruto and into the 21st century where he is currently undertaking his challenge since Madara Uhchiha; learning Java.....