More class conflict examples.

src/about_java_interop.rb

@@ -0,0 +1,89 @@
+require File.expand_path(File.dirname(__FILE__) + '/edgecase')
+
+include Java
+
+# Concepts
+# * Pull in a java class
+# * calling a method, Camel vs snake
+# * Resovling module/class name conflicts
+# * Showing what gets returned
+# * Ruby Strings  VS Java Strings
+# * Calling custom java class
+# * Calling Ruby from java???
+
+class AboutJavaInterop < EdgeCase::Koan
+  def test_using_a_java_library_class
+    java_array = java.util.ArrayList.new
+    assert_equal __(Java::JavaUtil::ArrayList), java_array.class
+  end
+
+  def test_java_class_can_be_referenced_using_both_ruby_and_java_like_syntax
+    assert_equal __(true), Java::JavaUtil::ArrayList == java.util.ArrayList
+  end
+
+  def test_include_class_includes_class_in_module_scope
+    assert_nil defined?(TreeSet) # __
+    include_class "java.util.TreeSet"
+    assert_equal __("constant"), defined?(TreeSet)
+  end
+
+  # THINK ABOUT IT:
+  #
+  # What if we use:
+  #
+  #   include_class "java.lang.String"
+  #
+  # What would be the value of the String constant after this
+  # include_class is run?  Would it be useful to provide a way of
+  # aliasing java classes to different names?
+
+  JString = java.lang.String
+  def test_also_java_class_can_be_given_ruby_aliases
+    java_string = JString.new("A Java String")
+    assert_equal __(java.lang.String), java_string.class
+    assert_equal __(java.lang.String), JString
+  end
+
+  def test_can_directly_call_java_methods_on_java_objects
+    java_string = JString.new("A Java String")
+    assert_equal __("a java string"), java_string.toLowerCase
+  end
+
+  def test_jruby_provides_snake_case_versions_of_java_methods
+    java_string = JString.new("A Java String")
+    assert_equal __("a java string"), java_string.to_lower_case
+  end
+
+  def test_jruby_provides_question_mark_versions_of_boolean_methods
+    java_string = JString.new("A Java String")
+    assert_equal __(true), java_string.endsWith("String")
+    assert_equal __(true), java_string.ends_with("String")
+    assert_equal __(true), java_string.ends_with?("String")
+  end
+
+  def test_java_string_are_not_ruby_strings
+    ruby_string = "A Java String"
+    java_string = java.lang.String.new(ruby_string)
+    assert_equal __(true), java_string.is_a?(java.lang.String)
+    assert_equal __(false), java_string.is_a?(String)
+  end
+
+  def test_java_strings_can_be_compared_to_ruby_strings_maybe
+    ruby_string = "A Java String"
+    java_string = java.lang.String.new(ruby_string)
+    assert_equal __(false), ruby_string == java_string
+    assert_equal __(true), java_string == ruby_string
+
+    # THINK ABOUT IT:
+    # Is there any possible way for this to be more wrong?
+  end
+
+  def test_however_most_methods_returning_strings_return_ruby_strings
+    java_array = java.util.ArrayList.new
+    assert_equal __("[]"), java_array.toString
+    assert_equal __(true), java_array.toString.is_a?(String)
+    assert_equal __(false), java_array.toString.is_a?(java.lang.String)
+  end
+
+
+end