These are the fruits of raphiolepis indica var. umbellata f. integerrima (too long!) or more commonly known as round-leaf Yeddo hawthorn. I wasn't that interested in the flowers, but these fruits are so round and so cute, and their green and purple color is so beautiful! I love them.
The fruits seem edible but according to a blog post, they're edible but not tasty, and the idea of eating them made me feel gross because these lovely fruits reminded me of Medama Oyaji (literally meaning "eyeball father"), i.e., one of the main characters of "GeGeGe no Kitaro." "GeGeGe no Kitaro" is a Japanese manga series about monsters, created in 1960 by Shigeru Mizuki and enjoyed by Japanese people for more than a half century. Medama Oyaji is a lovely father helping his son Kitaro with his vast knowledge, and is my favorite character of the series.