For thoroughness sake, let’s just mention the Q object method:
from django.db.models import Q
criterion1 = Q(question__contains="software")
criterion2 = Q(question__contains="java")
q = Question.objects.filter(criterion1 & criterion2)
Note the other answers here are simpler and better adapted for your use case, but if anyone with a similar but slightly more complex problem (such as needing “not” or “or”) sees this, it’s good to have the reference right here.