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InfluxDB
Power Real-Time Data Analytics at Scale. Get real-time insights from all types of time series data with InfluxDB. Ingest, query, and analyze billions of data points in real-time with unbounded cardinality.
I am not sure if this is what you are looking for, but allot of projects that I worked on used gson to convert between Java objects and JSON strings (https://github.com/google/gson). Maybe you should check it out.
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