You can update the path

1. Open the terminal and run the following command to edit the .bashrc file:

   nano ~/.bashrc

2. Look for any lines that incorrectly add Java to your PATH and remove any that reference /javac/bin/java.

   export PATH=$PATH:/usr/lib/jvm/jdk-21.0.5-oracle-x64/bin

3. Save and Reload the file

   source ~/.bashrc

4. Run Flutter doctor again to confirm your environment

   flutter doctor -v

N/B: If you have Android Studio installed, ensure that it is pointing to the correct JDK . https://www.geeksforgeeks.org/how-to-set-java-sdk-path-in-android-studio/