Represents the immediate subtype/supertype relation. Transitive super-/subtyping is expressed by the predicate subtype(#subClass, #superClass).

#class: classT
ID of an object type (class or interface)

#extendedClass: classT
ID of the direct supertype (superclass or superinterface).
Note: Interfaces that have no explicit super-interface in the source code have the class java.lang.Object as direct supertype.

public class HelloWorld extends HelloUniverse {            //#class
 ...
}
 
...
public class HelloUniverse {                               //#extendedClass
  ...	
}

extendsT(#class, #extendedClass).
classT(#class, 'null', 'HelloWorld', _).
classT(#extendedClass, 'null', 'HelloUniverse', _).

ast_relation('Java',extendsT,[
     ast_arg(sub,   mult(1,1,no ), id,   [classT]),
     ast_arg(super, mult(1,1,no ), id,   [classT])
]).