reveal-md

### **Instruction for Installing JDK 21 (LTS)**

#### **For macOS**
1. **Download the JDK**:
   - Go to the [Oracle JDK Downloads page](https://www.oracle.com/java/technologies/downloads/).
   - Select **Java SE Development Kit 21 (LTS)** and choose the macOS installer (`.dmg` file).

2. **Install the JDK**:
   - Double-click the downloaded `.dmg` file to open it.
   - Follow the installation prompts to complete the process.

3. **Verify Installation**:
   - Open the Terminal and run:
     ```bash
     java --version
     ```
   - You should see output like `java 21 LTS`.

4. **Set JAVA_HOME Environment Variable (Optional)**:
   - Open Terminal and edit your shell profile (`.zshrc` or `.bash_profile`):
     ```bash
     nano ~/.zshrc
     ```
   - Add the following line:
     ```bash
     export JAVA_HOME=$(/usr/libexec/java_home -v 21)
     ```
   - Save and reload the profile:
     ```bash
     source ~/.zshrc
     ```

---

#### **For Windows**
1. **Download the JDK**:
   - Visit the [Oracle JDK Downloads page](https://www.oracle.com/java/technologies/downloads/).
   - Select **Java SE Development Kit 21 (LTS)** and download the `.exe` installer for Windows.

2. **Install the JDK**:
   - Run the `.exe` file and follow the installation wizard.
   - By default, the JDK will be installed in `C:\Program Files\Java\jdk-21`.

3. **Verify Installation**:
   - Open Command Prompt and run:
     ```cmd
     java --version
     ```
   - You should see output like `java 21 LTS`.

4. **Set JAVA_HOME Environment Variable**:
   - Open **Control Panel** > **System** > **Advanced System Settings**.
   - In the **System Properties** window, click **Environment Variables**.
   - Under **System Variables**, click **New** and add:
      - **Variable Name**: `JAVA_HOME`
      - **Variable Value**: `C:\Program Files\Java\jdk-21`
   - Add `%JAVA_HOME%\bin` to the `Path` variable.