project JDK is not defined

It seems like you are facing an issue with your Java Development Kit (JDK) not being defined.

To resolve this issue, you may need to check if the JDK is installed on your system and if the path to the JDK is set correctly in your system environment variables.

Here are the steps to check if JDK is installed:

1. Open a command prompt or terminal window.
2. Type `java -version` and press Enter.
3. If JDK is installed, you will see the version information displayed. If not, you will need to download and install the JDK.

Once you have confirmed that JDK is installed, you can check if the path to the JDK is set correctly:

1. Right-click on My Computer or This PC and select Properties.
2. Click on Advanced system settings.
3. Click on the Environment Variables button.
4. Under System Variables, scroll down to find the Path variable and click Edit.
5. Check if the path to the JDK is included in the list of paths. If not, add it by clicking New and entering the path to the JDK.
6. Click OK to save the changes.

After these steps, try running your Java project again. If you still face issues, please provide more details about the error message you are receiving.