how to check java version in intellij

Natashya

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17-01-2025

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Knowing your Java version is crucial for development. IntelliJ IDEA, a popular Java IDE, makes checking this information straightforward. This guide shows you several ways to quickly determine which Java version your project is using within IntelliJ. We'll cover methods for both the JDK (Java Development Kit) used by your project and the JRE (Java Runtime Environment) used by IntelliJ itself.

Checking the Project SDK (JDK)

This is the most important check; it indicates the Java version your project compiles and runs against.

Method 1: Project Structure Dialog

1. Open Project Structure: Go to File -> Project Structure (or press Ctrl+Alt+Shift+S on Windows/Linux, or ⌘; on macOS).
2. Locate Project SDK: In the left-hand menu, select "Project".
3. View Project SDK: The "Project SDK" field displays the JDK version your project is configured to use. This will show the version number, e.g., 17, 11, or 8. You might also see the full JDK path.

Method 2: Module Settings (For Multi-Module Projects)

If you have a multi-module project, each module might use a different JDK.

1. Open Project Structure: As above, navigate to File -> Project Structure.
2. Select Modules: In the left-hand menu, choose "Modules".
3. Check Each Module: Select each module and examine its "Dependencies" tab. Look for the JDK listed under "Modules and Libraries".

Method 3: Build Output (Maven/Gradle)

Your build system (Maven or Gradle) also indicates the Java version. The output usually shows this during the compilation phase.

• Maven: Check your Maven build output in the "Build" tab or the console. Look for lines indicating the Java version used during compilation.
• Gradle: Similar to Maven, review Gradle's build output in the console or the IntelliJ "Build" tab. The Java version will be displayed during the build process.

Checking IntelliJ's JRE (Java Runtime Environment)

IntelliJ itself runs on a JRE. This is separate from the JDK your project uses.

Method 1: IntelliJ's About Dialog

1. Open About Dialog: Go to Help -> About.
2. Locate JRE: The "Build" section will typically list the JRE version IntelliJ is currently using.

Method 2: IntelliJ Configuration Files

IntelliJ's configuration files sometimes contain information about the JRE. However, this method is less user-friendly and requires navigating through configuration directories, which vary depending on your operating system. It’s generally more efficient to use the "About" dialog.

Troubleshooting:

• Incorrect JDK: If the project SDK is wrong, you'll need to change it in the Project Structure dialog (Method 1 above). You may need to add the correct JDK if it's not already listed. Find your JDK's installation path and point IntelliJ to it.
• Multiple JDKs: Ensure you've selected the correct JDK from the list of available SDKs in Project Structure. If needed, you can add a new JDK using the "+" button within the "Project SDK" settings.
• Build Errors: Errors during compilation frequently indicate an incompatibility between your project's code and the selected JDK. Check your project's dependencies and build files. Ensure compatibility between libraries and your chosen JDK.

By using these methods, you can efficiently check and manage the Java versions used by both your IntelliJ instance and your Java projects. Remember to always verify that your project's JDK is the correct one to avoid compatibility issues during development.