I traveled on Japan Airlines JAL B787-8 from Moscow to Tokyo Narita in May 2019. This video shows JAL B787-8 Business and Economy Class details. Despite the flight was great in terms of seating, food and service. There was one terrible design that made me couldn't sleep.
Find out in the vlog. Japan Airlines is the only airline in the world that have 2-4-2 (8 abreast) economy seating on the Boeing 787 Dreamliner. The standard economy seating is 3-3-3 (9 abreast)