During the first 2 centuries BC and first century AD numerous would be messiahs and Jewish militant leaders made claims to being of the tribe of Judah and sons of David. How honest were they? According to the Jewish Encyclopedia any tribal claims were meaningless. Any claim to belong to an ancient family line was little more than a propaganda device. Why? Two reasons. First, During the long centuries of Babylonian, Syrian , Greek and Roman rule tribal distinction became impossible. Intermarrying between tribes was not unusual. I estimate that if only 1% of the Jews under this foreign rule married a fellow Jew of a different tribe in less than 200 years or 10 generations nearly every Jew could rightly claim to be of every tribe! Others are welcome to do some math as I am only estimating, but the point is clear. Any claim to be of the tribe of Judah would be nothing more than a politically handy exaggeration. The possible exception is the Levites who may possibly have maintained some semblence of tribal purity due to their occupation thru much of this time.
Secondly, The family records were lost according to Jewish authorities during the reign of Herod 1 (possibly in a earthquake and fire in the temple in 31BC). This was a surprise to me as I was taught that this loss occured in 70CE. The JWs make much of this as disqualifying any self proclaimed Messiahs after 70CE as it was then impossible to "prove" his heritage. According to the Jewish records it really was not possible for about 100 years before that. And as explained above any claim to a tribal identity was meaningless. The Gospel writers include these claims for Jesus but do so in a way that is consistent with the facts here. The "geneologies" are obvious creations, and dealt with in literary fashion. I'm sure this has been discussed here before so I will not expound on the fictive aspects of the two geneologies.