Strangeness with calling super class methods from JRuby

Ruby JRuby
1

Hi all

I’m encountering this rather strange issue.

I have this setup going.

JavaClass.java
public class JavaClass
{
public void pushString() { … }
}

RubyClass.rb
class RubyClass < JavaClass
def pushString
super.pushString # error! (NoMethodError) undefined method
`pushString’
end

end

=====
However, if I have this
JavaClass.java
public class JavaClass implements Serializable
{
public void pushString() {…}

public void writeReplace() {… } // method from Serializable
}

RubyClass.rb
class RubyClass < JavaClass
java_implements ‘Serializable’
java_signature ‘public Object writeReplace()’
def writeReplace
super.pushString #works…
return…
end

end

=====
BUT this doesn’t:
Interface.java
public interface Interface
{
public void test();
public Object test2();
}

JavaClass.java
public class JavaClass implements Serializable, Interface
{
public void pushString() {…}

public void writeReplace() {… } // method from Serializable

public void test() { … }

public Object test2() { return “S”; }
}

RubyClass.rb
class RubyClass < JavaClass
java_implements ‘Serializable, Interface’
java_signature ‘public Object writeReplace()’
def writeReplace
super.pushString #works…
return…
end

java_signature ‘public void test()’
def test
super.pushString # no method error again from nil class
end

java_signature ‘public void test2()’
def test2
super.pushString # no method error , but this time it says
(NoMethodError) undefined method `pushString’ for “S”:String
end

end

=====
Why is this so…?
I’m curious as to why I can call super methods from Serializable’s
interface methods, but doing the same for my own interface doesn’t work.
Also, the last error is even stranger, why would it say “S”:String,
which is the return for my super class’s method?

What’s the best practice for calling super methods? java_send or super?

Thanks!

Regards
Angel

2

From Programming in Ruby by Dave T. and Andy H.

“In example 2, we create a subclass of class Song, overriding both the
initialize
and to s methods. In both of the new methods we use the super keyword to
invoke
the equivalent method in our parent class. In Ruby, super is not a
reference to a parent
class; instead it is an executable statement that reinvokes the current
method, skipping
any definition in the class of the current object.”

Cheers,
Luís Landeiro R.