From http://www.behindthename.com/name/joshua
JOSHUA
Gender: Masculine
Usage: English, Biblical
Pronounced: JAH-shə-wə (English), JAW-shwə (English) [key]
From the Hebrew name יְהוֹשֻׁעַ (Yehoshu'a) meaning "YAHWEH is salvation". Joshua was one of the twelve spies sent into Canaan by Moses in the Old Testament. After Moses died Joshua succeeded him as leader of the Israelites. As an English name, Joshua has been in use since the Protestant Reformation.
The name Jesus comes from a Greek translation of the Aramaic short form יֵשׁוּעַ (Yeshu'a), which was the real name of Jesus.