When default methods were introduced in Java 8, some developers thought they would be the same as abstract classes. That’s not true, however, because interfaces can’t have state.

Another option for writing an Excel file is to write the output in CSV (comma-separated value) format. You can also read a CSV file from a Java application.

Java does enable the option to mark a class as final to eliminate the ability to perform inheritance complete, but that is often too heavy of a hammer to drop. Marking a class as final prevents all ...