assert_equal __, java_array.toString.is_a?(java.lang.String)
end
+ def test_java_collections_are_enumerable
+ java_array = java.util.ArrayList.new
+ java_array << "one" << "two" << "three"
+ assert_equal __, java_array.map { |item| item.upcase }
+ end
+
+ # ------------------------------------------------------------------
+
+ # Open the Java ArrayList class and add a new method.
+ class Java::JavaUtil::ArrayList
+ def multiply_all
+ result = 1
+ each do |item|
+ result *= item
+ end
+ result
+ end
+ end
+
+ def test_java_class_are_open_from_ruby
+ java_array = java.util.ArrayList.new
+ java_array.add_all([1,2,3,4,5])
+
+ assert_equal __, java_array.multiply_all
+ end
+
end