Task 1: Introduction to Java

1. Setting Up Java:

   • Ensure that the JDK is installed on your computer.

   • Verify the installation by running the following command in the terminal/command prompt:

       java -version
       javac -version
     

2. Writing Your First Java Program:

   • Open a text editor and write the following Java program:

       public class HelloWorld {
           public static void main(String[] args) {
               System.out.println("Hello, World!");
           }
       }
     

   • Save the file as HelloWorld.java.

3. Compiling and Running the Java Program:

   • Open the terminal/command prompt and navigate to the directory where HelloWorld.java is saved.

   • Compile the Java program using the javac command:

       javac HelloWorld.java
     

   • Run the compiled Java program using the java command:

       java HelloWorld
     

   • Observe the output: Hello, World!

Task 2: Exploring Java Features

1. Case Sensitivity:

   • Modify the HelloWorld.java program by changing System.out.println to system.out.println.

   • Compile the program and observe the error message.

   • Discuss why Java is case-sensitive.

2. Comments and Escape Sequences:

   • Add comments to your HelloWorld.java program using both single-line (//) and multi-line (/* ... */) comments.

   • Modify the System.out.println statement to include an escape sequence (e.g., \n for a new line, \t for a tab).

   • Recompile and run the program to see the effects of the escape sequences.

Example:

    public class HelloWorld {
        public static void main(String[] args) {
            // This is a single-line comment
            /* This is a
               multi-line comment */
            System.out.println("Hello,\n\tWorld!");
        }
    }

Task 3: Understanding Java Bytecode and JVM

1. Exploring Bytecode:

   • After compiling HelloWorld.java, locate the HelloWorld.class file in the same directory.

   • Open the .class file in a text editor (it will appear as gibberish) and discuss with your friend what bytecode is and how it is used by the JVM.

Excercices

Exercise 1: Print Your Name

Question: Write a Java program to print your name on the console.

Expected Output:

My name is John Doe

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Exercise 2: Print Your Index Number

Question: Write a Java program to print your index number on the console.

Expected Output:

My index number is 12345

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Exercise 3: Print Your Name and Index Number

Question: Write a Java program to print both your name and index number on the console.

Expected Output:

My name is Jane Doe
My index number is 67890

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Exercise 4: Print a Pattern

Question: Write a Java program to print the following pattern using System.out.println():

Expected Output:

*
**
***
****
*****

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Exercise 5: Print a Welcome Message

Question: Write a Java program to print a welcome message for your college or university.

Expected Output:

Welcome to HNDIT College!

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Exercise 6: Print Multiple Lines

Question: Write a Java program to print the following lines using a single System.out.println() statement:

Expected Output:

Line 1
Line 2
Line 3

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Exercise 7: Print a Box Using Asterisks

Question: Write a Java program to print the following box using asterisks (*):

Expected Output:

*****
*   *
*   *
*   *
*****

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Instructions for Students:

1. Write each program in a separate .java file.

2. Compile the program using the javac command:

    javac FileName.java
   

3. Run the program using the java command:

    java FileName
   

4. Observe the output and ensure it matches the expected result.

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Learning Outcomes:

• Understand the basic structure of a Java program.

• Learn how to use System.out.println() to print output.

• Gain familiarity with compiling and running Java programs.

• Practice writing simple Java programs to build confidence.