Well that's a very good question based on general knowledge.
Both Indonesian and Polish flag has same red and white bars. But the difference is that the red bar in Indonesian flag in on the upper part and in Polish flag the red bar's position is in bottom.
But the meanings are different in two countries for two flag.
For Indonesia the red bar is the symbol of peoples blood, and the white bar is representing peoples spirit. The flag for Indonesia was first designed on 13th century as Javan Majapahit Empire flag. That time the flag had nine white and red bars. Indonesian flag has a nam in their country. That is "Sang Saka Merah Putih". The meaning is "lofty bicolor red and white".
On the other hand the polish flag was designed on 1919. The white bar in Poland's flag is representing the hope for peace of polish citizens. And the red bar is to remind the socialism that days had gone.
For your kind information another country that is Monaco has the same flag as Indonesia. But that is a coincidence.
Thanks for reading. Hope you like this.