Python4j's types by default come with all of the python primitive types supported. These types include: 1. STR: the string type, mapped to java's string type 2. INT: the integer type, mapped to java's long type 3. FLOAT: the float type, mapped to java's double type 4. BOOL: the boolean type, mapped to java's boolean type 5. BYTES: the bytes type, mapped to java's byte array