diff --git a/Sources/FuzzilliCli/Profiles/ArkProfile.swift b/Sources/FuzzilliCli/Profiles/ArkProfile.swift
index 0f6234dbda01b8f7a6cd2dfb3e030f94325258d8..9e498b4ff932dd0b31ba62cf0ff0701665d86726 100644
--- a/Sources/FuzzilliCli/Profiles/ArkProfile.swift
+++ b/Sources/FuzzilliCli/Profiles/ArkProfile.swift
@@ -27,9 +27,19 @@ fileprivate let RunNearStackLimitGenerator = CodeGenerator("RunNearStackLimitGen
 
 /// ArkTS Generators
 fileprivate let ArkTSObjectInstanceGenerator = ValueGenerator("ArkTSObjectInstanceGenerator") { b, n in
-    let builtin = chooseUniform(from: ["Stack", "HashMap", "HashSet", "LinkedList", "List", "ArrayList"])
+    let builtin = chooseUniform(from: ["Stack", "HashMap", "HashSet", "LinkedList", "List", "ArrayList", "TreeMap", "TreeSet"])
     let constructor = b.loadBuiltin(builtin)
-    b.construct(constructor)
+    if ["TreeMap", "TreeSet"].contains(builtin) && probability(0.2) {   //custom comparator for TreeMap and TreeSet will be generated only in 20% of cases
+        let comparator = b.buildPlainFunction(with: .parameters(n: 2)) { args in
+           assert(args.count >= 2)
+           // The comparator is either ascending or descending with equal probability
+           let result = b.compare(args[0], with: args[1], using: chooseUniform(from: [.greaterThan, .lessThan]))
+           b.doReturn(result)
+        }
+        b.construct(constructor, withArgs: [comparator])
+    } else {
+        b.construct(constructor)
+    }
 }
 
 /// ArkTS Collections Generators
@@ -51,6 +61,10 @@ fileprivate let arkTSLinkedList = ILType.iterable + ILType.object(ofGroup: "Link
 fileprivate let arkTSList = ILType.iterable + ILType.object(ofGroup: "List", withProperties: ["length"], withMethods: ["add", "insert", "has", "get", "getLastIndexOf", "getIndexOf", "equal", "removeByIndex", "remove", "replaceAllElements", "forEach", "sort", "getSubList", "clear", "set", "convertToArray", "isEmpty", "getFirst", "getLast"])
 /// Type of a ArkTS ArrayList object.
 fileprivate let arkTSArrayList = ILType.iterable + ILType.object(ofGroup: "ArrayList", withProperties: ["length"], withMethods: ["add", "insert", "has", "getIndexOf", "getLastIndexOf", "removeByIndex", "remove", "removeByRange", "replaceAllElements", "forEach", "sort", "subArrayList", "clear", "clone", "getCapacity", "convertToArray", "isEmpty", "increaseCapacityTo", "trimToCurrentLength"])
+/// Type of a ArkTS TreeMap object.
+fileprivate let arkTSTreeMap = ILType.iterable + ILType.object(ofGroup: "TreeMap", withProperties: ["length"], withMethods: ["isEmpty", "hasKey", "hasValue", "get", "getFirstKey", "getLastKey", "setAll", "set", "remove", "getLowerKey", "getHigherKey", "replace", "clear", "keys", "values", "forEach", "entries"])
+/// Type of a ArkTS TreeSet object.
+fileprivate let arkTSTreeSet = ILType.iterable + ILType.object(ofGroup: "TreeSet", withProperties: ["length"], withMethods: ["isEmpty", "has", "getFirstValue", "getLastValue", "add", "remove", "getLowerValue", "getHigherValue", "popFirst", "popLast", "clear", "values", "forEach", "entries"])
 
 /// Tpye of a ArkTS CollectionsMap object
 fileprivate let collectionsMap = ILType.iterable + ILType.object(ofGroup: "SharedMap", withProperties: ["size"], withMethods: ["entries", "keys", "values", "clear", "delete", "forEach", "get", "has", "set"])
@@ -67,6 +81,10 @@ fileprivate let arkTSLinkedListConstructor = ILType.constructor([] => arkTSLinke
 fileprivate let arkTSListConstructor = ILType.constructor([] => arkTSList)
 /// Type of the ArkTS ArrayList constructor builtin.
 fileprivate let arkTSArrayListConstructor = ILType.constructor([] => arkTSArrayList)
+/// Type of the ArkTS TreeMap constructor builtin.
+fileprivate let arkTSTreeMapConstructor = ILType.constructor([.opt(.function([.anything, .anything] => .boolean))] => arkTSTreeMap)
+/// Type of the ArkTS TreeSet constructor builtin.
+fileprivate let arkTSTreeSetConstructor = ILType.constructor([.opt(.function([.anything, .anything] => .boolean))] => arkTSTreeSet)
 
 /// Type of the ArkTs CollectionsMap constructor builtin.
 fileprivate let collectionsMapConstructor = ILType.constructor([.object()] => collectionsMap)
@@ -183,7 +201,7 @@ fileprivate let arkTSLinkedLists = ObjectGroup(
     ]
 )
 
-// ObjectGroup modelling ArkTS List objects
+/// ObjectGroup modelling ArkTS List objects
 fileprivate let arkTSLists = ObjectGroup(
     name: "List",
     instanceType: arkTSList,
@@ -213,7 +231,7 @@ fileprivate let arkTSLists = ObjectGroup(
     ]
 )
 
-// ObjectGroup modelling ArkTS ArrayList objects
+/// ObjectGroup modelling ArkTS ArrayList objects
 fileprivate let arkTSArrayLists = ObjectGroup(
     name: "ArrayList",
     instanceType: arkTSArrayList,
@@ -243,6 +261,59 @@ fileprivate let arkTSArrayLists = ObjectGroup(
     ]
 )
 
+/// ObjectGroup modelling ArkTS TreeMap objects
+fileprivate let arkTSTreeMaps = ObjectGroup(
+    name: "TreeMap",
+    instanceType: arkTSTreeMap,
+    properties: [
+        "length"    : .number,
+    ],
+    methods: [
+        "isEmpty"  :         [] => .boolean,
+        "hasKey"   :         [.anything] => .boolean,
+        "hasValue" :         [.anything] => .boolean,
+        "get"      :         [.anything] => .anything,
+        "getFirstKey" :      [] => .anything,
+        "getLastKey" :       [] => .anything,
+        "setAll"   :         [.object(ofGroup: "TreeMap")] => .undefined,
+        "set"      :         [.anything, .anything] => .object(),
+        "remove"   :         [.anything] => .anything,
+        "getLowerKey" :      [.anything] => .anything,
+        "getHigherKey" :     [.anything] => .anything,
+        "replace"  :         [.anything, .anything] => .boolean,
+        "clear"    :         [] => .undefined,
+        "keys"     :         [] => .object(),      //returns an iterator
+        "values"   :         [] => .object(),      //returns an iterator
+        "forEach"  :         [.function([.opt(.anything), .opt(.anything), .opt(arkTSTreeMap)] => .undefined), .opt(.object())] => .undefined,
+        "entries"  :         [] => .object(),      //returns an iterator
+    ]
+)
+
+/// ObjectGroup modelling ArkTS TreeSet objects
+fileprivate let arkTSTreeSets = ObjectGroup(
+    name: "TreeSet",
+    instanceType: arkTSTreeSet,
+    properties: [
+        "length"    : .number,
+    ],
+    methods: [
+        "isEmpty"  :         [] => .boolean,
+        "has"      :         [.anything] => .boolean,
+        "getFirstValue" :    [] => .anything,
+        "getLastValue" :     [] => .anything,
+        "add"      :         [.anything] => .boolean,
+        "remove"   :         [.anything] => .boolean,
+        "getLowerValue" :    [.anything] => .anything,
+        "getHigherValue" :   [.anything] => .anything,
+        "popFirst" :         [] => .anything,
+        "popLast" :          [] => .anything,
+        "clear"    :         [] => .undefined,
+        "values"   :         [] => .object(),      //returns an iterator
+        "forEach"  :         [.function([.opt(.anything), .opt(.anything), .opt(arkTSTreeSet)] => .undefined), .opt(.object())] => .undefined,
+        "entries"  :         [] => .object(),      //returns an iterator
+    ]
+)
+
 let arkProfile = Profile(
     processArgs: { randomize in
         var args = [
@@ -266,6 +337,8 @@ let arkProfile = Profile(
                 var LinkedList = arkPrivate.Load(arkPrivate.LinkedList);
                 var List = arkPrivate.Load(arkPrivate.List);
                 var ArrayList = arkPrivate.Load(arkPrivate.ArrayList);
+                var TreeMap = arkPrivate.Load(arkPrivate.TreeMap);
+                var TreeSet = arkPrivate.Load(arkPrivate.TreeSet);
 
                 function bgc() {
                     for(let i=0; i<0x10000; i+=1) {new String();}
@@ -316,6 +389,8 @@ let arkProfile = Profile(
         "LinkedList"                                       : arkTSLinkedListConstructor,
         "List"                                             : arkTSListConstructor,
         "ArrayList"                                        : arkTSArrayListConstructor,
+        "TreeMap"                                          : arkTSTreeMapConstructor,
+        "TreeSet"                                          : arkTSTreeSetConstructor,
     ],
 
     additionalObjectGroups: [
@@ -326,6 +401,8 @@ let arkProfile = Profile(
         arkTSLinkedLists,
         arkTSLists,
         arkTSArrayLists,
+        arkTSTreeMaps,
+        arkTSTreeSets,
     ],
 
     optionalPostProcessor: nil