public static Object project(Schema source, Object record, Schema target) throws SchemaProjectorException {
        checkMaybeCompatible(source, target);
        if (source.isOptional() && !target.isOptional()) {
            if (target.defaultValue() != null) {
                if (record != null) {
                    return projectRequiredSchema(source, record, target);
                } else {
                    return target.defaultValue();
                }
            } else {
                throw new SchemaProjectorException("Writer schema is optional, however, target schema does not provide a default value.");
            }
        } else {
            if (record != null) {
                return projectRequiredSchema(source, record, target);
            } else {
                return null;
            }
        }
    }
This method projects a value between compatible schemas and throws exceptions when non-compatible schemas are provided
@param source the schema used to construct the record
@param record the value to project from source schema to target schema
@param target the schema to project the record to
@return the projected value with target schema
@throws SchemaProjectorException if the target schema is not optional and does not have a default value
connect/api/src/main/java/org/apache/kafka/connect/data/SchemaProjector.java