Xu Hướng 12/2022 # Lesson: A Closer Look At The “Hello World!” Application (The Java™ Tutorials / 2023 # Top 19 View | Hoisinhvienqnam.edu.vn

Xu Hướng 12/2022 # Lesson: A Closer Look At The “Hello World!” Application (The Java™ Tutorials / 2023 # Top 19 View

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Trail: Getting Started

class HelloWorldApp { public static void main(String[] args) { System.out.println("Hello World!"); } } /** * The HelloWorldApp class implements an application that * simply prints "Hello World!" to standard output. */ class HelloWorldApp { public static void main(String[] args) { System.out.println("Hello World!"); } } /* text */ The compiler ignores everything from /* to */. /** documentation */ Javadoc™ tool documentation . The compiler ignores everything from

The following bold text begins the class definition block for the "Hello World!" application:

/** * The HelloWorldApp class implements an application that * simply displays "Hello World!" to the standard output. */ class HelloWorldApp { public static void main(String[] args) { System.out.println("Hello World!"); } }

As shown above, the most basic form of a class definition is:

class name { . . . }

The keyword class begins the class definition for a class named name, and the code for each class appears between the opening and closing curly braces marked in bold above. Chapter 2 provides an overview of classes in general, and Chapter 4 discusses classes in detail. For now it is enough to know that every application begins with a class definition.

The following bold text begins the definition of the main method:

/** * The HelloWorldApp class implements an application that * simply displays "Hello World!" to the standard output. */ class HelloWorldApp { public static void main(String[] args) { System.out.println("Hello World!"); } }

In the Java programming language, every application must contain a main method whose signature is:

public static void main(String[] args)

The modifiers public and static can be written in either order (public static or static public), but the convention is to use public static as shown above. You can name the argument anything you want, but most programmers choose "args" or "argv".

The main method accepts a single argument: an array of elements of type String.

public static void main(String[] args)

This array is the mechanism through which the runtime system passes information to your application. For example:

java MyApp arg1 arg2

Each string in the array is called a command-line argument. Command-line arguments let users affect the operation of the application without recompiling it. For example, a sorting program might allow the user to specify that the data be sorted in descending order with this command-line argument:

-descending

The "Hello World!" application ignores its command-line arguments, but you should be aware of the fact that such arguments do exist.

Finally, the line:

System.out.println("Hello World!");

uses the System class from the core library to print the "Hello World!" message to standard output. Portions of this library (also known as the "Application Programming Interface", or "API") will be discussed throughout the remainder of the tutorial.

Lesson: A Closer Look At The “Hello World!” Application / 2023

Now that you’ve seen the “Hello World!” application (and perhaps even compiled and run it), you might be wondering how it works. Here again is its code:

class HelloWorldApp { public static void main(String[] args) { System.out.println("Hello World!"); } } /** * The HelloWorldApp class implements an application that * simply prints "Hello World!" to standard output. */ class HelloWorldApp { public static void main(String[] args) { System.out.println("Hello World!");// Display the string. } }

The following bold text begins the class definition block for the “Hello World!” application:

/** * The HelloWorldApp class implements an application that * simply displays "Hello World!" to the standard output. */ class HelloWorldApp { public static void main(String[] args) { System.out.println("Hello World!");

As shown above, the most basic form of a class definition is:

The keyword class begins the class definition for a class named name, and the code for each class appears between the opening and closing curly braces marked in bold above. Chapter 2 provides an overview of classes in general, and Chapter 4 discusses classes in detail. For now it is enough to know that every application begins with a class definition.

The following bold text begins the definition of the main method:

/** * The HelloWorldApp class implements an application that * simply displays "Hello World!" to the standard output. */ class HelloWorldApp { public static void main(String[] args) { System.out.println("Hello World!");

In the Java programming language, every application must contain a main method whose signature is:

public static void main(String[] args)

The modifiers public and static can be written in either order ( public static or static public), but the convention is to use public static as shown above. You can name the argument anything you want, but most programmers choose “args” or “argv”.

The main method accepts a single argument: an array of elements of type String.

public static void main(String[] args)

This array is the mechanism through which the runtime system passes information to your application. For example:

Each string in the array is called a command-line argument. Command-line arguments let users affect the operation of the application without recompiling it. For example, a sorting program might allow the user to specify that the data be sorted in descending order with this command-line argument:

The “Hello World!” application ignores its command-line arguments, but you should be aware of the fact that such arguments do exist.

Finally, the line:

System.out.println("Hello World!");

uses the System class from the core library to print the “Hello World!” message to standard output. Portions of this library (also known as the “Application Programming Interface”, or “API”) will be discussed throughout the remainder of the tutorial.

Strong Words Takes An Unpretentious Look At Books / 2023

Strong Words takes an unpretentious look at books

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Ed Needham loves books. And he also knows a thing or two about making magazines; he was the editor of FHM in its late 90s heyday, and he went on to edit FHM in the USA, then Rolling Stone and Maxim. But his latest editorial position is altogether more humble – Strong Words is a new magazine that takes a fresh and unpretentious look at books, and Ed is its editor, publisher, marketing manager and van driver.

He dropped into the Stack office to speak about his new publishing project, the ways in which it has changed since it started earlier this year, and how he plans to develop it over the coming months. As is often the case with independent publishers who find they have to do everything themselves, Ed is open about the things he finds most difficult, and excited by the opportunity to tweak all aspects of the magazine as he goes. There will be lots of magazine makers who feel very familiar with his struggles over marketing, distribution and production.

If you enjoy this one, check out our archive on Soundcloud or iTunes for lots more conversations with magazine makers. (If you’re particularly interested in the business side of publishing, you might want to jump straight to our recent episodes with Jeff Taylor from Courier magazine, or Conor Purcell from The Magazine Blueprint.) And remember to follow us wherever you get your podcasts, so we can drop our future episodes straight into your feed as soon as they’re ready.

strong-words.co.uk

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Letter R Preschool Activities (And Free Preschool Lesson Plan: R Is For Recycle!) * Lovin’ Life With Littles / 2023

Whether it’s Earth Day, your regular Preschool, or you just want some ideas for activities, kids will love these preschool activities about recycling. Through games, music, books, crafts, and more, today we learn all about the letter R! Kids will enjoy and learn from these creative and hands-on Letter R activities for preschool. This post includes all you need to teach the free preschool lesson plan R is for Recycle.

This lesson continues our alphabet lesson plan series and is intended to help make your experience teaching preschool in your home easier, educational, and more fun.

Preschool at Home

Most importantly, the best part of doing preschool at home is the chance to teach my kids (and whatever buddies are with us) the things that really matter, laugh together, and shower them with love at this young and important age. My hope is that these lesson plans and activities help you in your efforts to do the same.

If you haven’t seen my quick tips for getting started with successful home preschool, check them out.

Use and share these plans to talk, sing, read, write, and play your way through the alphabet; these kinds of activities are the foundation of building strong readers. You can use our full lesson plans, or, of course, pick individual activities to do with the Littles in your life. Lastly, I am also a budget-friendly Mama, so no worries there: our activities are always easy on the pocketbook. Now, let’s get to it!

This post contains some affiliate links for your convenience. By shopping through those links you support Lovin’ Life with Littles at no additional cost to you. Thank you for your support! Read my Full Disclosure .

Visit the Preschool Lesson Plan Index to see what free plans are published or in the works!

Update: You can now get ALL of the Alphabet Lesson Plans, Checklists, and Printables, (plus Bonus Ideas and 75+ exclusive preschool printables!) all in one budget-friendly digital product… A to Z and Beyond! Preschool Curriculum.

INTRODUCTION

First off, gather on the floor for circle time and start with a welcome song. We have been singing, “Hello to All the Children of the World”. Each week we have been briefly spotlighting one of the countries or features in the song.

Last week we talked about the line that says, “We speak in many different ways!” One way to speak that is not in the song is with sign language. Last week we learned how to say hello, children, and world in sign language.

Today, we’ll learn signs for the line “We live in different places from all around the world.”

To make the sign for “live,” make two thumbs up near your hips and then bring them upward in front of you. “Different” is signed by beginning with the pointer fingers crossed, then pointing them away from each other. We can sign “place or area” by holding up the hand with palm down and fingers spread out, and then circling the hand. To make the sign for “around,” you make the sign for place but move your hand around an upheld pointer finger. Lastly, we learned the sign for world last week: make W’s with both hands and turn them around each other.

Each of these words can be found in this super helpful signing dictionary that shows how to make the signs.

Write: Rice Writing with Letter R

I introduced how today we are learning about the letter R. Both the uppercase and lowercase letter R are made of straight and curvy shapes.

We practiced writing the letter R in rice. I put some rice onto a plate with a rim, so the rice didn’t fall everywhere. Rice is a fun manipulative that kids love to play in, so it makes it a great way to practice writing.

After practicing the letter R, we practiced writing several other letters she remembered.

Talk: The Sound of the Letter R

The sound of letter R seems to be an easier one to remember when we attach it to the sound a pirate makes, “Rrrrrrr Matey!” So we each made a pirate hook and did our best pirate impressions.

Then we took turns saying words that begin with the letter R.

Talk: Rhyme Time

One fun word that starts with the letter R is rhyme. We talked about what it means to rhyme and gave some examples. Then the Littles tried to think of a rhyming word for words that start with the letter R, like red, run, rad, real, and read.

When the kids think of a rhyming word, you can sing the little song, “Run, fun these words rhyme. (Repeated three times.) So rhyme along with me.” The tune is ” Skip to My Lou.”

Rhyming is a hard concept, so if this is a challenge, don’t worry! Help the kids think of rhyming words by saying, “Does fat rhyme with run? How about fun?” It’s very age appropriate to think of nonsense rhyming words as well.

Sing: Exercise, Rhyme, and Freeze

We got moving and practiced more rhyming with this fun song ” Exercise, Rhyme, and Freeze.” The movements are simple, and the pace is easy to follow.

Play: Rhythm Sticks

The next R-word we focused on was rhythm. After introducing how rhythm is the beat of music, we used paper towel tubes for rhythm sticks. We practiced keeping a steady rhythm, then copied a few simple rhythms from this online drum lesson.

Lastly, I turned on some drum music (this Led Zeppelin Rock and Roll Drum Cover is pretty fun), and we drummed away with our rhythm sticks.

The great thing about these rhythm sticks is that they are pretty harmless. If your little drummers get pretty enthusiastic, the sticks won’t hurt the furniture, walls, or other drummers. 🙂

Next, I pulled out a recycling item and asked, “What could this be used for?” We talked about a plastic container, but any item will work. I encouraged my little to use her imagination and think of as many ideas as possible.

It could be a cereal bowl, vase, way to catch bugs, or swimming pool for her plastic animals!

I explained how when we reuse objects (either as they are intended or in creative ways), it saves us money and creates less waste. This is really good for the earth.

When we recycle something, people find creative ways to break that object down and make it into something new. This is also good for the environment.

Read: A Trip to the Recycling Center

If you don’t want to purchase a book, check your library. Most will have nonfiction titles about recycling, and you should be able to find one that fits your needs.

Play: Recyclables Sort

I had saved up our recyclables for the week and put them all in a laundry basket. Then we talked about how to sort the items into paper and plastic. (We only did two categories in order to keep it simple, but you could do as many as you want, of course.)

The kids worked together to sort the recyclables into separate boxes.

If your Littles are already familiar with sorting recyclables, you could make this into a fun relay race.

Read: The Adventures of a Plastic Bottle: A Story about Recycling

This is an entertaining story about a plastic bottle that serves many purposes. The book is detailed enough about the process of recycling that even my older kids found it interesting, but the main ideas are still simple enough for little kids. Overall it’s an amusing way to learn more about recycling.

After reading these books about recycling, it was time to make our own! I wanted to share the free printable for My Little Book of Recycling with you. The printable can be folded and colored. (It needs one small cut with scissors, which I did.)

Additionally, kids can write their names on the front cover and practice writing the letter R by coloring or tracing the R’s in Reduce, Reuse, and Recycle.

The book teaches the basics of how we can reduce, reuse, and recycle to help our planet Earth.

My Little really enjoyed reading her own little book that she made.

Play: Recyclable Inventions

This next recycling activity was a favorite for the kids and me because I loved seeing imagination in action. We happened to have my big kids home too for this activity, and it was a hit with everyone.

We simply got out all those recyclables again and said, “Create.”

Some of the ideas were complex and required copious amounts of tape. Others were really simple and still very fun.

I was amazed with all the ideas my kids came up with. From musical instruments to pretend vacuums, the options are truly limitless.

An added bonus that I hadn’t thought of was that my kids enjoyed playing with their inventions for a long time in the days that followed.

Making these recyclables creations was a fun part of our preschool day, but it would also be a great stand-alone activity for Earth Day or any day.

Sing: Robot Dance

One of us made a robot out of recyclables, so it was fitting to sing and move to the Robot Dance. However, robot is a great r-word anyway and a fun way to move for everyone.

Play: Red Light, Green Light

We had a little more time left, so we used that to play a game of Red Light, Green Light. This classic game is actually really good for kids as it helps them practice both color recognition and the skill of linking movement to sensory input.

I made a red light manipulative by cutting one red circle and one green one from construction paper and then taping them to either side of a ruler. We use this for Red Light, Green Light and singing (stop and start with the flip).

To mix up the game, and especially if you’re playing in a smaller space like us, use a different kind of movement each round. For example, kids can crawl one round and crab walk the next.

Eat: Foods that Begin with the Letter R

We had a little snack of raisins and red peppers.

Here are some foods that start with the letter R: radishes, Red Vines, raspberries, rice, raspberry flavored things like fig bars, red peppers, raisins, Rice Krispies (or Rice Krispie Treats), ratatouille, ravioli, Reese’s, refried or red beans, rolls, Ritz crackers, rice cakes, or anything red.

Talk: Gratitude for Earth

While the kids finished their snack, we talked about Earth. What do you love about nature and where we live? We can be very grateful for Earth and show that gratitude by the way we take care of it.

We discussed how we can take good care of Earth by not littering or wasting and recycling, like we learned about today. I asked a few questions about taking care of the earth and answered questions from my Little.

Sing: Goodbye Song

We closed up by reviewing our letter of the day: what Letter R looks and sounds like.

Lastly, we sang our goodbye song and see you next week!

Our next preschool lesson will be Letter S is for Seasons. It has a lot of fun and educational activities!

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Lesson: A Closer Look At The “Hello World!” Application (The Java™ Tutorials / 2023

Trail: Getting Started

class HelloWorldApp { public static void main(String[] args) { System.out.println("Hello World!"); } } /** * The HelloWorldApp class implements an application that * simply prints "Hello World!" to standard output. */ class HelloWorldApp { public static void main(String[] args) { System.out.println("Hello World!"); } } /* text */ The compiler ignores everything from /* to */. /** documentation */ Javadoc™ tool documentation . The compiler ignores everything from

The following bold text begins the class definition block for the "Hello World!" application:

/** * The HelloWorldApp class implements an application that * simply displays "Hello World!" to the standard output. */ class HelloWorldApp { public static void main(String[] args) { System.out.println("Hello World!"); } }

As shown above, the most basic form of a class definition is:

class name { . . . }

The keyword class begins the class definition for a class named name, and the code for each class appears between the opening and closing curly braces marked in bold above. Chapter 2 provides an overview of classes in general, and Chapter 4 discusses classes in detail. For now it is enough to know that every application begins with a class definition.

The following bold text begins the definition of the main method:

/** * The HelloWorldApp class implements an application that * simply displays "Hello World!" to the standard output. */ class HelloWorldApp { public static void main(String[] args) { System.out.println("Hello World!"); } }

In the Java programming language, every application must contain a main method whose signature is:

public static void main(String[] args)

The modifiers public and static can be written in either order (public static or static public), but the convention is to use public static as shown above. You can name the argument anything you want, but most programmers choose "args" or "argv".

The main method accepts a single argument: an array of elements of type String.

public static void main(String[] args)

This array is the mechanism through which the runtime system passes information to your application. For example:

java MyApp arg1 arg2

Each string in the array is called a command-line argument. Command-line arguments let users affect the operation of the application without recompiling it. For example, a sorting program might allow the user to specify that the data be sorted in descending order with this command-line argument:

-descending

The "Hello World!" application ignores its command-line arguments, but you should be aware of the fact that such arguments do exist.

Finally, the line:

System.out.println("Hello World!");

uses the System class from the core library to print the "Hello World!" message to standard output. Portions of this library (also known as the "Application Programming Interface", or "API") will be discussed throughout the remainder of the tutorial.

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