maddi Java demo

A small Maven project for trying maddi's IDE plugins by hand: open it, run the analysis, and check that the hints, the gutter icons and the tool window say what this project says they should.

Every class shows one or two of maddi's annotations, and its Javadoc says what to look for. The popular annotations (@NotModified/@Modified, @Immutable, @Container, @Independent) recur throughout; the rare ones have a class each. EXPECTED-HINTS.md lists, per declaration, exactly what the analysis computes.

The classes are adapted from the test batteries of maddi-modification-analyzer and maddi-modification-link.

Opening it

• IntelliJ IDEA: File → Open on this directory, as a Maven project. Install the maddi plugin, set its JDK (25 or later) under Settings → Tools → maddi, then Tools → Analyze with maddi.
• Builds with mvn compile on JDK 21 or later. The only dependencies are io.codelaser:maddi-annotation and io.codelaser:maddi-support 0.9.5 from Maven Central, for the contracts and the eventually immutable classes.

What is where

Package	Classes	Shows
demo.modification	Counter, Bag, ListTools, Item, Elements, Registry	@Modified / @NotModified on methods, fields and parameters; @Container; @Modified(hc=true) where only the elements change
demo.immutable	Point, Pair, Color, Snapshot, Tags, LazyName, Shape, Circle	@ImmutableContainer, with and without hidden content; @FinalFields; @Final; a contract on an interface
demo.independence	Inventory, Box, Wrapper	@Independent, @Independent(hc=true), @Dependent; @UnmodifiableView
demo.method	Sentence, Checks, Person, Ranges	@Fluent, @Identity, @GetSet, @Commutable
demo.nullability	Lookup	@NotNull / @Nullable
demo.eventual	Config, Document	@Mark, @Only, @TestMark, @Immutable(after=...), @NotModified(after=...)
demo.rare	Audit, Settings, SettingsClient, Report, Worker, Clock, Strings	@IgnoreModifications, @StaticSideEffects, @Finalizer, @AllowsInterrupt, @Singleton, @ExtensionClass, @UtilityClass
demo.guard	WrongImmutable, WrongContainer	wrong contracts on purpose: two guard findings, with their why-chain

Annotations the IDE does not show today

As of 2026-10-27 (regenerated after the fixes of that day), so that a missing hint is not mistaken for a broken plugin:

• Nullability: a public parameter whose method accepts null without failing is @Nullable, even when no call passes null (maddi-mod#68): concatenated (Tags.tag), appended to a StringBuilder (Sentence.word, Report.line), tested for null (Checks.orDefault), or stored where null is already possible (Person.setName). A parameter stored into a field's list that holds no null stays @NotNull (Bag.add). Lookup itself comes out as intended.
• Contracts the analyzer reads but the IDE does not echo: @UtilityClass (ListTools), @Commutable (Ranges), @AllowsInterrupt (Worker).
• Not used by the analyzer at all: @Singleton (Clock), @ExtensionClass (Strings), @BeforeMark; @Docstring is documentation, not analysis.