.j
3 claimants
3 primary
0 secondary
shared primary (3)
SWH popularity
Distinct files in the full Software Heritage archive (2026-06-04 export), dated by first appearance, following Desmazières, Di Cosmo, Lorentz (MSR 2025). Case-aggregated. citation.
248.9K
total files
57.8K
first seen 2021–2025 (23.2%)
2016
median year (half its files since)
Case variants in archive: .j (232.0K), .J (16.9K) — aggregated above.
Attribution status
This extension is attributed to Jasmin; JASS; Objective-J as primary by 5 authoritative claims.
Claimants (5)
Languages that list
.j among their extensions. Strength reflects whether the upstream source treated it as their primary extension.| Language | Source | Strength |
|---|---|---|
| Jasmin | linguist | primary |
| Jasmin | pygments | primary |
| JASS | linguist | primary |
| Objective-J | linguist | primary |
| Objective-J | pygments | primary |
Wikidata says… (2)
File formats, image formats, audio codecs and other non-PL
entities that claim
.j on Wikidata
(property P1195) or in the Wikipedia infobox.
Source: data/derived/external_extension_index.csv.
Click Use as new PL on any row to open the
Add-PL form pre-filled with that entry's name, Wikipedia/Wikidata
URL, and this extension — one submission creates the PL + claim.
| Format | Class (Wikidata P31) | Suggested label | MIME | Notes | Action |
|---|---|---|---|---|---|
| Jasmin file format Q129922769 file format | file format | — | — | — | Use as new PL ↗ |
| Objective-J source code file Q130391411 file format | file format | — | text/x-objective-j | — | Use as new PL ↗ |
Disambiguation rules (3)
Linguist heuristics that decide, by content, which language a
.j file actually is.| Rule | Predicts | Kind | Predicates (truncated) | Measured on SWH |
|---|---|---|---|---|
h/linguist/.j/0 | Jasmin | predicates | [{"kind": "any", "regexes": ["^\\s*\\.(?:class|super|method|end\\s+method|limit|field|source|bytecode)\\b"]}] | |
h/linguist/.j/1 | Objective-J | predicates | [{"kind": "any", "regexes": ["^\\s*@(?:import|implementation|protocol|interface|typedef|end)\\b"]}] | |
h/linguist/.j/2 | JASS | predicates | [{"kind": "any", "regexes": ["^\\s*(?:constant\\s+)?(?:function|native)\\s+\\w+\\s+takes\\b", "^\\s*end(?:function|globals|loop)\\s*$", "^\\s*(?:call|set|local|exitwhen)\\s+\\S"]}] |
SWH-mined examples (0)
No archived examples for .j in our local mirror yet.