Yes the Dems are in quite a pickle with Hillary having to fight a 3 front war between Trump, Sanders and her criminal investigations. If she loses California, that's going to make for one doozy of a convention. Remember when the Dems were salivating over a GOP contested convention?
Sanders could get every single vote in California, and still lose the nomination.
Hillary Clinton will win & secure the nomination on June 7th,
before California comes in. New Jersey with 142 delegates, and New Mexico with 43 will be reporting. Prior to June 7th Puerto Rico will be voting, and I imagine Hillary Clinton will do very well there as they are Hispanic.
Hillary Clinton needs 73 more delegates
Bernie Sanders needs 841 more delegates.
Primary schedule
Jun 4 Virgin Islands Caucus 12
Jun 5 Puerto Rico Primary 67
Jun 7 California 546
Jun 7 Montana 27
Jun 7 New Jersey 142
Jun 7 New Mexico 43
Jun 7 North Dakota Caucus 23
Jun 7 South Dakota 25
Jun 14 District of Columbia 46
total delegates left 913
Now you can understand why everyone is scratching their heads as to why Bernie Sanders hasn't dropped out of this race.