[

{

"id": "email",

"title": "Email",

"className": "Email (built-in tutorial)",

"complexity": "simple",

"factors": ["typestate"],

"blurb": "A four-step protocol for composing an email: sender, then recipient, then optional subject, then body. Hand-authored to introduce @StateSet and @StateRefinement.",

"violation": "Calling to(\"Bob\") in state emptyEmail; required: senderSet(this) or receiverSet(this)."

},

{

"id": "abstract-undoable-edit",

"title": "AbstractUndoableEdit",

"className": "javax.swing.undo.AbstractUndoableEdit",

"complexity": "simple",

"factors": ["typestate"],

"blurb": "An edit alternates between aliveDone and aliveNotDone before being killed. Calling redo() while already done is a protocol error.",

"violation": "redo() requires aliveNotDone(this), but this is in state aliveDone."

},

{

"id": "zip-file",

"title": "ZipFile",

"className": "java.util.zip.ZipFile",

"complexity": "simple",

"factors": ["typestate"],

"blurb": "Open a zip, read entries, then close it. Touching a closed ZipFile is a use-after-close bug.",

"violation": "stream() requires opened(this), but this is in state closed."

},

{

"id": "throwable",

"title": "Throwable",

"className": "java.lang.Throwable",

"complexity": "simple",

"factors": ["typestate"],

"blurb": "initCause() is only legal once — on a Throwable created without a cause. Calling it on one that already has a cause throws at runtime; LiquidJava catches it statically.",

"violation": "initCause() requires noThrowable(this), but this is in state withThrowable."

},

{

"id": "choice-callback",

"title": "ChoiceCallback",

"className": "javax.security.auth.callback.ChoiceCallback",

"complexity": "moderate",

"factors": ["typestate", "conditional"],

"blurb": "The constructor lands in single or multiple based on a boolean argument. setSelectedIndexes() is only valid in multiple. The transition is conditional on a parameter value — a ternary in the spec.",

"violation": "setSelectedIndexes() requires multiple(this), but this is in state single."

},

{

"id": "image-write-param",

"title": "ImageWriteParam",

"className": "javax.imageio.ImageWriteParam",

"complexity": "complex",

"factors": ["typestate", "orthogonal", "conditional"],

"blurb": "Two independent state machines on the same object: a tiling axis and a compression axis, each with its own (start → explicit → set) progression. Calls on one axis don't perturb the other.",

"violation": "getCompressionType() requires compressionExplicit(this) or compressionSet(this), but the compression axis is in state startCompression."

},

{

"id": "buffered-reader",

"title": "BufferedReader",

"className": "java.io.BufferedReader",

"complexity": "complex",

"factors": ["typestate"],

"blurb": "open ⇄ marked, both heading to closed. reset() only works after a mark(); double-resetting is a classic mistake.",

"violation": "reset() requires marked(this), but this is in state open."

},

{

"id": "socket",

"title": "Socket",

"className": "java.net.Socket",

"complexity": "complex",

"factors": ["typestate"],

"blurb": "Six states: unconnected, bound, connected, inputShutdown, outputShutdown, bothShutdown, closed. Many setters are restricted to the connected state.",

"violation": "setReuseAddress() requires connected(this), but this is in state inputShutdown."

},

{

"id": "uuid",

"title": "UUID",

"className": "java.util.UUID",

"complexity": "complex",

"factors": ["refinement", "typestate"],

"blurb": "The classifier is bit-math on the constructor argument: (mostSigBits/4096) % 16 == 1 → timeBased, else dceSecurityNameRandom. clockSequence() is rejected on the random branch — an SMT predicate decides which state you're in.",

"violation": "clockSequence() requires maybeTime(this) or timeBased(this), but this is in state dceSecurityNameRandom."

}

]