Javadoc
Converter class to convert an entity (represented as Map<String, Object>) to be conformed to associated schema,
or a value (represented as Object) to be conformed to associated type of the field.
More clearly, conversion makes the type of each of value be conformed to the type of field.
For example, suppose the value is 1 which type is Integer and the type is LONG which type of Java is Long.
After conversion, the value will be 1 which type is Long.
Currently it does a magic conversion with only BOOLEAN and Number types (BYTE, SHORT, INTEGER, LONG, FLOAT, DOUBLE).
For other types it just works like a type validator.