If you're looking for a meeting place or a good stop around ½ or halfway between San Jose and Oakland, you can try Union City, CA, which is about half an hour northwest of San Jose, or about half an hour southeast of Oakland.
About ¼ or a fourth of the way, you can stop at Curtner, CA. This is about 12 minutes north of San Jose.
About ⅓ or a third of the way, you can stop at Fremont, CA. This is about 17 minutes north of San Jose.
About ¾ or three fourths of the way, you can stop at San Leandro, CA. This is about half an hour northwest of San Jose, or about 12 minutes southeast of Oakland.
If you drive straight through without stopping at all, the total distance is 40 miles. The distances shown above don't include local roads to get into each town, so if you're planning a long road trip, make sure you factor in traffic and road conditions, rest stop breaks, and interesting detours along the way. If you're in a rush, you can do the trip with zero stops, and your total travel time would be around 48 minutes.