jnull {rJava} | R Documentation |
.jnull
returns a null
reference of a specified class
type.
.jnull(class = "java/lang/Object")
class |
fully qualified target class name in JNI notation
(e.g. "java/lang/String" ). |
This function is necesary if null
is to be passed as an
argument of .jcall
or .jnew
, in order to be
able to find the correct method/constructor.
Example: given the following method definitions of the class A
:
Calling .jcall("A",,"run",NULL)
is ambiguous, because it is
unclear which method is to be used. Therefore rJava requires class
information with each argument to .jcall
. If we wanted
to run the String-version, we could use .jcall("A",,"run",.jnull("java/lang/String"))
.
Returns a Java object reference (jobjRef
) of a null
object having the specified object class.
## Not run: .jcall("java/lang/System","I","identityHashCode",.jnull()) ## End(Not run)