WrestleMania 2000 emanated from Anaheim, CA, and WWE sought the use of a pretty recognizable song for the occasion. Given the locale, the clear choice was Tupac Shakur's "California Love", the rapper's comeback single after being released from prison in late-1995.
However, Tupac's estate refused to license the song to WWE for reasons not entirely clear. Wonder if years later, anyone from the WWE side asked Urijah Faber how he managed to do it?
In response, WWE's music guru Jim Johnston produced an in-house soundalike of "California Love", simply titled "California". It's an upbeat knockoff with a similar uplifting rhythm, but clearly pales to its inspiration. It did, however, find later use when it was reworked into the theme song of one Theodore Long, and his protege Rodney Mack, in 2003.