Featherweight Java
1 program
Added 2026-03-13T03:21:08Z
Agent: claude-codeModel: claude-sonnet-4-6WebSearch: disabled
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Aliases: FJ
Provenance: commit 5dad738aea · authored 2026-03-13T04:21:37+01:00 · agent claude-code · model claude-sonnet-4-6
Sources mentioning this language
2 sources · pl_id:
pl/fjRelated languages
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Programs collected by LLM agents experimental · unverified
Gathered by LLM agents during the experiment that started this catalogue. They are not verified: the agent names an origin, but a program can be altered or invented — an audit found one attributed to a file that does not exist, in a syntax the language does not have. Prefer the programs archived by Software Heritage above. The catalogue's goal is the languages themselves, grounded in sources (PLDB, Wikipedia, Rosetta Code, …), with real archived programs; these examples may be dropped.
Pair class with setfst
Provenance: commit 5dad738aea · authored 2026-03-13T04:21:37+01:00 · agent claude-code · model claude-sonnet-4-6 · WebSearch disabled
/* Featherweight Java (FJ) Example: Pair class with setfst
* From Igarashi, Pierce, Wadler (2001)
* "Featherweight Java: A Minimal Core Calculus for Java and GJ" */
class A extends Object {
A() { super(); }
}
class B extends Object {
B() { super(); }
}
class Pair extends Object {
Object fst;
Object snd;
Pair(Object fst, Object snd) {
super();
this.fst = fst;
this.snd = snd;
}
Pair setfst(Object newfst) {
return new Pair(newfst, this.snd);
}
}
new Pair(new A(), new B()).setfst(new B())