Download of JDiff X 1.09 for Mac was on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The program is included in Productivity Tools. The actual developer of this free software for Mac is Artman21 Inc. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe.
From the developer:
JDiff X is a document comparison plug-in for Jedit X. It displays the changes made in Jedit X documents. You can compare any types of documents that can be read with Jedit X, including plain text of various text encodings or rich text documents. You can also merge the differences instantly using its merge button or the contextual menu.
You may want to check out more Mac applications, such as PitStop Extreme, 3dissue or FileOpenInstaller, which might be related to JDiff X.