code: private void init() {
  
  		factories.put(NotEmptyQuery.class,     new NotEmptyQueryFactory(this));
  		factories.put(FulltextQuery.class,     new KeywordQueryFactory(this));
  		factories.put(SpatialQuery.class,      new SpatialQueryFactory(this));
  		factories.put(GroupQuery.class,        new GroupQueryFactory(this));
  		factories.put(RangeQuery.class,        new RangeQueryFactory(this));
  		factories.put(ExactQuery.class,        new KeywordQueryFactory(this));
  		factories.put(ArrayQuery.class,        new ArrayQueryFactory(this));
  		factories.put(EmptyQuery.class,        new EmptyQueryFactory(this));
  		factories.put(TypeQuery.class,         new TypeQueryFactory(this));
  		factories.put(UuidQuery.class,         new UuidQueryFactory(this));
  		factories.put(RelationshipQuery.class, new RelationshipQueryFactory(this));
  		factories.put(ComparisonQuery.class,   new ComparisonQueryFactory(this));
  
  		converters.put(Boolean.class, new BooleanTypeConverter());
  		converters.put(String.class,  new StringTypeConverter());
  		converters.put(Date.class,    new DateTypeConverter());
  		converters.put(Long.class,    new LongTypeConverter());
  		converters.put(Short.class,   new ShortTypeConverter());
  		converters.put(Integer.class, new IntTypeConverter());
  		converters.put(Float.class,   new FloatTypeConverter());
  		converters.put(Double.class,  new DoubleTypeConverter());
  		converters.put(byte.class,    new ByteTypeConverter());
  	}
docs: ----- private methods -----