Microsoft buildup new website for open-source project

微软建立了一个新的网站,用于支持和推广开源项目的发展。
Lab 1 - Chapter 1 Java Language Programming | Chapter 1: Foundations of Java and First Steps Course: Java Language Programming Instructor: Ahsan Shehzad Date: September 1, 2025 Lab Objective: Your First Java Program ✅ Goal By the end of this lab, you will have a fully functional Java development environment and will have successfully written, compiled, and run the "Hello, World!" program for our course project, MyContactManager . Prerequisites A computer with a modern operating system (Windows, macOS, or Linux). An active internet connection to download the required software. Final Result Step 1: Install the Java Development Kit (JDK) Goal Install the core toolkit that allows us to build and run Java applications. Instructions 1. Navigate to a trusted OpenJDK distributor like Adoptium. 2. Download the latest LTS (Long-Term Support) version installer for your operating system (e.g., Temurin 17 or 21). 3. Run the installer and follow the on-screen prompts, accepting the default settings. Ensure the "Add to PATH" option is checked if available. Verification Code Open a new terminal or command prompt after the installation is complete and run these commands:Expected Result The terminal should print the installed Java version (e.g., openjdk version "17.0.8" ). If you see an error like 'command not found' , your system's PATH variable may be misconfigured. Please ask for assistance. Step 2: Install a Professional IDE Goal Install IntelliJ IDEA, a powerful Integrated Development Environment (IDE) that will help us write, manage, and debug our code efficiently. Instructions 1. Go to the official JetBrains website: jetbrains.com/idea/download/. 2. Download the installer for the Community Edition, which is free. 3. Run the installer, accepting the default options. You can create a desktop shortcut for convenience. Expected Result The IntelliJ IDEA application should now be installed on your computer. You can launch it from your applications folder, desktop, or start menu. Step 3: Create the 'MyContactManager' Project Goal Create a new, organized project inside IntelliJ to house all the code for our course application. Instructions 1. Launch IntelliJ IDEA. If prompted, you can skip the initial configuration plugins. 2. On the welcome screen, click "New Project". 3. In the New Project window: Enter the Name: MyContactManager Set the Language: Java Set the Build system: IntelliJ For JDK: Select the JDK you just installed from the dropdown. It should be detected automatically. 4. Click "Create". # Check the Java Runtime Environment version java -version # Check the Java Compiler version javac -version 1 2 3 4 5Expected Result IntelliJ will create a project structure. In the Project Explorer pane on the left, you'll see a folder named src . This src (source) folder is where all of our .java files will live. Step 4: Write and Run the main Class Goal Write the entry point for our application and execute it to see output. Instructions 1. In the Project Explorer, right-click the blue src folder. 2. Select New -> Java Class . 3. In the pop-up, enter the name MyContactManager and press Enter. 4. Type (or copy) the following code into the editor window that appears. 5. To run the program, click the green play button ▶ that appears to the left of the public static void main line. Code Expected Result A "Run" tool window will appear at the bottom of IntelliJ, and you should see the following text output: Welcome to MyContactManager! /** * The main class for our MyContactManager application. * This class serves as the entry point for the program. */ public class MyContactManager { /** * The main method is automatically executed when the program runs. * @param args Command-line arguments (we will ignore these for now). */ public static void main(String[] args) { // System.out.println() is a built-in Java command // to print a line of text to the console. System.out.println("Welcome to MyContactManager!"); } } 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15Step 5: Experiment and See an Error Goal Understand how the compiler helps us by catching syntax errors before the program runs. Instructions 1. Introduce an error: In your MyContactManager.java file, deliberately delete the semicolon ( ; ) at the end of the System.out.println(...) line. 2. Observe the IDE: Notice how IntelliJ immediately underlines the code in red and shows an error message if you hover over it. This is called real-time error checking, a key feature of an IDE. 3. Attempt to run: Click the green play button ▶ again. Erroneous Code Expected Result The program will fail to compile. The "Run" window will show a compile-time error, which will read something like java: ';' expected . This demonstrates how the compiler acts as a strict grammar checker for the Java language, preventing broken code from ever running. Simply add the semicolon back to fix it. 🚀 Challenges Finished the lab early? Try these small challenges to solidify your understanding. 1. Personalize It Modify the program to print a personalized welcome message, like "Hello, [Your Name]!" . 2. Multi-Line Output Add a second System.out.println() statement on a new line to print a description of the application, such as "This app will help you manage your contacts." . 3. Explore an IDE Warning The String[] args parameter in the main method is currently grayed out. Hover over it. The IDE is telling you it's an "unused parameter." This isn't an error, but a friendly warning that you've declared something you never use. public class MyContactManager { public static void main(String[] args) { // This line now has a deliberate syntax error! System.out.println("Welcome to MyContactManager!") // <-- Missing semicolon } } 1 2 3 4 5 6 答案是什么
09-22
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