// Inserter.java
@FunctionalInterface
public interface Inserter extends EventHandler<ActionEvent> {

	public abstract void handle(ActionEvent e);

	default void insert(parameters...) {
		...inserting stuff to db
	}
}

// Other.java: insert stuff to db on button click

// This works normally

button.setOnAction(new Inserter() {
			@Override
			public void handle(ActionEvent e) {
				insert(parameters...);
			}
		}
	);

// Possible to implement it this way? Cannot find symbol "insert"
button.setOnAction(
	(e) -> insert(parameters...)
);