Data conversion between Java and B-Prolog

The following table converts data from Java to Prolog:

Java	Prolog
Integer	integer
Double	real
Long	integer
BigInteger	integer
Boolean	integer
Character	string (list of codes)
String	string (list of integers)
Object array	list
Object	$addr(I1,I2)

Notice that no primitive data type can be converted into Prolog. Data conversion from Prolog to Java follows the same protocol but a string is converted to an array of Integers rather than a String, and a Prolog atom is converted to a Java String.

Prolog	Java
integer	Integer
real	Double
atom	String
string	Object array
list	Object array
structure	Object

The conversion between arrays and lists needs further explanation. A Java array of some type is converted into a list of elements of the corresponding converted type. For instance, an Integer array is converted into a list of integers. In contrast, a Prolog list, whatever type whose elements is, is converted into an array of Object type. When an array element is used as a specific type, it must be casted to that type.