Jython

Issue2866

classification
Title: Interface default methods disregarded by the method resolver
Type: behaviour Severity: normal
Components: Core Versions:
Milestone:
process
Status: open Resolution:
Dependencies: Superseder:
Assigned To: Nosy List: nfalliere
Priority: Keywords:

Created on 2020年03月05日.23:01:08 by nfalliere, last changed 2020年03月05日.23:01:08 by nfalliere.

Messages
msg13008 (view) Author: Nicolas Falliere (nfalliere) Date: 2020年03月05日.23:01:08
Per https://www.jython.org/jython-old-sites/archive/221/archive/22/userguide.html#overloaded-java-method-signatures: "Java methods are allowed to be overloaded for different signatures (types and number of arguments). When different versions of the method differ in the number of arguments that they expect, the appropriate method can be easily determined from the number of arguments passed to the method."
With Jyhon 2.7 (2.7.1, and the current RC of 2.7.2 as well), this works fine for regular class methods, eg:
class A {
 void f(int a) {
 return a + 1;
 }
 void f(int a, int b) {
 return a+b;
 }
}
in Jython:
A().f(4) # will select the proper overload
A().f(1, 2) # will select the proper overload 
However, for interfaces:
interface I {
 default void f(int a) {
 return f(a, 1);
 }
 void f(int a, int b);
}
class A implements I {
 void f(int a, int b) {
 return a+b;
 }
}
in Jython:
x = someMethodReturningAnObjectImplementingI()
x.f(4) # fail, complains that method should receive 2 args
So it looks like default methods, a language addition of Java 8, may not be seen by the Jython interpreter. Any chance to get that added in a future 2.7.x maintenance release?
History
Date User Action Args
2020年03月05日 23:01:08nfallierecreate

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