Most of there names mean something in their native langue. Koreans, Chinese and Native Americans have similar practices.
For example
Boys
Taro=first born
Jiro=second born
Akemi Beauty of dawn
Akihiko=Bright
Ryuu=Dragon
Yuuda=Hero + great
Girls.
Usagi=rabbit
Mizuki= tree of water (literally, water tree)
MEGUMI= blessing
Shizu=Quiet
Wakaba=young leaf
For more interesting articles about Japanese names.
Japanese Girls' Names - Japanese Names - Issendai's Lair
Japanese Boys' Names - Japanese Names - Issendai's Lair
Behind the Name: Name
What's in a (Japanese) name? | The Japan Times Online