Top 4 Java Diff Projects

java-diff-utils

0 1,192 4.4 Java

Diff Utils library is an OpenSource library for performing the comparison / diff operations between texts or some kind of data: computing diffs, applying patches, generating unified diffs or parsing them, generating diff output for easy future displaying (like side-by-side view) and so on.
sirix

44 1,079 9.2 Java

SirixDB is an an embeddable, bitemporal, append-only database system and event store, storing immutable lightweight snapshots. It keeps the full history of each resource. Every commit stores a space-efficient snapshot through structural sharing. It is log-structured and never overwrites data. SirixDB uses a novel page-level versioning approach.

Project mention: Show HN: Integer Map Data Structure | news.ycombinator.com | 2024-01-24

We're using a similar trie structure as the main document (node) index in SirixDB[1]. Lately, I got some inspiration for different page-sizes based on the ART and HAMT basically for the rightmost inner pages (as the node-IDs are generated by a simple sequence generator and thus also all inner pages (we call them IndirectPage) except for the rightmost are fully occupied (the tree height is adapted dynamically depending on the size of the stored data. Currently, always 1024 references are stored to indirect child pages, but I'll experiment with smaller sized, as the inner nodes are simply copied for each new revision, whereas the leaf pages storing the actual data are versioned themselfes with a novel sliding snapshot algorithm.
You can simply compute from a unique nodeId each data is assigned (64bit) the page and reference to traverse on each level in the trie through some bit shifting.
[1] https://github.com/sirixdb/sirix

InfluxDB

www.influxdata.com sponsored

Power Real-Time Data Analytics at Scale. Get real-time insights from all types of time series data with InfluxDB. Ingest, query, and analyze billions of data points in real-time with unbounded cardinality.
gumtree

6 857 8.1 Java

An awesome code differencing tool

Project mention: Pijul: Version-Control Post-Git • Goto 2023 | news.ycombinator.com | 2023-08-11

I'm not familiar with Pijul, and haven't finished watching this presentation, but IME the problems with modern version control tools is that they still rely on comparing lines of plain text, something we've been doing for decades. Merge conflicts are an issue because our tools are agnostic about the actual content they're tracking.
Instead, the tools should be smarter and work on the level of functions, classes, packages, sentences, paragraphs, or whatever primitive makes sense for the project and file that is being changed. In the case of code bases, they need to be aware of the language and the AST of the program. For binary files, they need to be aware of the file format and its binary structure. This would allow them to show actually meaningful diffs, and minimize the chances of conflicts, and of producing a corrupt file after an automatic merge.
There has been some research in this area, and there are a few semantic diffing tools[1,2,3], but I'm not aware of this being widely used in any VCS.
Nowadays, with all the machine learning advances, the ideal VCS should also use ML to understand the change at a deeper level, and maybe even suggest improvements. If AI can write code for me, it could surely understand what I'm trying to do, and help me so that version control is entirely hands-free, instead of having to fight with it, and be constantly aware of it, as I have to do now.
I just finished watching the presentation, and Pijul seems like an iterative improvement over Git. Nothing jumped out at me like a killer feature that would make me want to give it a try. It might be because the author focuses too much on technical details, instead of taking a step back and rethinking what a modern VCS tool should look like today.
[1]: https://semanticdiff.com/
[2]: https://github.com/trailofbits/graphtage
[3]: https://github.com/GumTreeDiff/gumtree

openapi-diff

3 746 8.7 Java

Utility for comparing two OpenAPI specifications.

Project mention: Using OpenAPI to Detect Breaking Changes in tRPC | dev.to | 2023-10-16

Introducing our star player for detecting breaking changes: OpenAPI Diff. The good news? You can fire it up locally with Docker. Here’s how:

NOTE: The open source projects on this list are ordered by number of github stars. The number of mentions indicates repo mentiontions in the last 12 Months or since we started tracking (Dec 2020).