DataNucleus supports persistence to heterogeneous datastores and this plugin provides persistence to JSON.
'org.datanucleus:datanucleus-json:2.0.1'
<dependency>
<groupId>org.datanucleus</groupId>
<artifactId>datanucleus-json</artifactId>
<version>2.0.1</version>
</dependency>
<dependency org="org.datanucleus" name="datanucleus-json" rev="2.0.1"/>
"org.datanucleus", "datanucleus-json", "2.0.1"