It can also come from (a) meaning "second, Asia" combined with (ki) meaning "hope". My cockatiels name is Aki. After months of not deciding on a name for him, named him meaning hope for the devastating tsunami 2011 in Japan.
Any times I know of where a Japanese guy goes by Aki, it's part of a longer name. Here are some of the other meanings of Aki, depending on which kanji character you use: glitter/glisten bright (different kanji than the one for light) chapter of a book pleasant/cheerful