4J41 questions

4J41 answers

• what does " |= "and " ^= " mean in java? [duplicate]
• Converting mongo array to object with key-value pair
• Aggregate match pipeline not equal to in MongoDB
• Mongodb Aggregation Framework: Does $group use index?
• using $and with $match in mongodb
• mongod shell doesn't start, data/db doesn't exsist
• Java Mongodb numberlong query