If Java is not recognized as internal or external command, you need to make sure that the installation is not problematic and its path is recognized as system variables.

You can use the Command Prompt to check if you are using Java 32-bit or 64-bit. It is an easy step, just open CMD with administrative privileges. Now, paste the following command.

Navigate to jdk.java.net and download your platform’s zip file. Extract the Java 21 zip file to a sensible location on your filesystem. Configure the JAVA_HOME environment variable. Add the JDK’s \bin ...

java - version Command 'java' not found, but can be installed with: sudo apt install default-jre. If the command indicates that Java is not found, proceed with the next steps. Update Ubuntu’s package ...