diff --git a/app/src/main/java/ru/project/MyCollectors.java b/app/src/main/java/ru/project/MyCollectors.java
new file mode 100644
index 0000000..20840c3
--- /dev/null
+++ b/app/src/main/java/ru/project/MyCollectors.java
@@ -0,0 +1,10 @@
+package ru.test.maven.spring;
+import java.util.stream.Collector;
+public class MyCollectors
+{
+    private MyCollectors() {
+    }
+    public static <T> Collector<T, MyList<T>, MyList<T>> toMyList() {
+        return new MyListCollector<>();
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/ru/project/MyListCollector.java b/app/src/main/java/ru/project/MyListCollector.java
new file mode 100644
index 0000000..f731379
--- /dev/null
+++ b/app/src/main/java/ru/project/MyListCollector.java
@@ -0,0 +1,41 @@
+package ru.test.maven.spring;
+import java.util.Collections;
+import java.util.Set;
+import java.util.function.BiConsumer;
+import java.util.function.BinaryOperator;
+import java.util.function.Function;
+import java.util.function.Supplier;
+import java.util.stream.Collector;
+public class MyListCollector <T> implements Collector<T, MyList<T>, MyList<T>>
+{
+    @Override
+    public Supplier<MyList<T>> supplier()
+    {
+        return () -> new MyLinkedList<>();
+    }
+    @Override
+    public BiConsumer<MyList<T>, T> accumulator() {
+
+        return (list, element) -> list.add(element);
+    }
+    @Override
+    public BinaryOperator<MyList<T>> combiner() {
+        return (list1, list2) -> {
+            for (int i = 0; i < list2.size(); i++) {
+                list1.add(list2.get(i));
+            }
+            return list1;
+        };
+    }
+    @Override
+    public Function<MyList<T>, MyList<T>> finisher()
+    {
+        return list -> list;
+    }
+    @Override
+    public Set<Collector.Characteristics> characteristics() {
+        return java.util.Set.of(
+                Collector.Characteristics.IDENTITY_FINISH
+        );
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/ru/project/collectors/MyCollectors.java b/app/src/main/java/ru/project/collectors/MyCollectors.java
new file mode 100644
index 0000000..d0d7cf5
--- /dev/null
+++ b/app/src/main/java/ru/project/collectors/MyCollectors.java
@@ -0,0 +1,15 @@
+package ru.project.collectors;
+import java.util.stream.Collector;
+
+public class MyCollectors
+{
+    private MyCollectors() {
+
+    }
+
+    public static <T> Collector<T, MyList<T>, MyList<T>> toMyList()
+    {
+        return new MyListCollector<>();
+
+    }
+}
diff --git a/app/src/main/java/ru/project/collectors/MyListCollector.java b/app/src/main/java/ru/project/collectors/MyListCollector.java
new file mode 100644
index 0000000..bb168e4
--- /dev/null
+++ b/app/src/main/java/ru/project/collectors/MyListCollector.java
@@ -0,0 +1,43 @@
+package ru.project.collectors;
+import java.util.Collections;
+import java.util.Set;
+import java.util.function.BiConsumer;
+import java.util.function.BinaryOperator;
+import java.util.function.Function;
+import java.util.function.Supplier;
+import java.util.stream.Collector;
+public class MyListCollector <T> implements Collector<T, MyList<T>, MyList<T>>
+{
+    @Override
+    public Supplier<MyList<T>> supplier()
+    {
+        return () -> new MyLinkedList<>();
+    }
+
+    @Override
+    public BiConsumer<MyList<T>, T> accumulator() {
+
+        return (list, element) -> list.add(element);
+    }
+
+    @Override
+    public BinaryOperator<MyList<T>> combiner() {
+        return (list1, list2) -> {
+            list1.addAll(list2);
+            return list1;
+        };
+    }
+
+    @Override
+    public Function<MyList<T>, MyList<T>> finisher()
+    {
+        return list -> list;
+    }
+
+    @Override
+    public Set<Collector.Characteristics> characteristics() {
+        return java.util.Set.of(
+                Collector.Characteristics.IDENTITY_FINISH
+        );
+    }
+}
diff --git a/app/src/main/java/ru/project/finder/StudentOccurrenceIndexFinder.java b/app/src/main/java/ru/project/finder/StudentOccurrenceIndexFinder.java
new file mode 100644
index 0000000..7e7c3d2
--- /dev/null
+++ b/app/src/main/java/ru/project/finder/StudentOccurrenceIndexFinder.java
@@ -0,0 +1,125 @@
+package ru.project.finder;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+public class StudentOccurrenceIndexFinder
+{
+    public int[] findOccurrences(MyList<Student> students, Student target) {
+        if (students == null) {
+            throw new IllegalArgumentException();
+        }
+        if (target == null) {
+            throw new IllegalArgumentException();
+        }
+        if (students.isEmpty()) {
+            return new int[0];
+        }
+        int size = students.size();
+        int threadCount = calculateThreadCount(size);
+        int chunkSize = countChunkSize(size, threadCount);
+
+        ExecutorService executor = Executors.newFixedThreadPool(threadCount);
+        MyList<Future<MyList<Integer>>> futures = new MyLinkedList<>();
+
+        for (int i = 0; i < threadCount; i++) {
+            int fromIndex = i * chunkSize;
+            int toIndex = Math.min(fromIndex + chunkSize, size);
+
+            if (fromIndex >= toIndex) {
+                break;
+            }
+
+            final int start = fromIndex;
+            final int end = toIndex;
+
+            Future<MyList<Integer>> future = executor.submit(() -> {
+                return findInRange(students, target, start, end);
+            });
+            futures.add(future);
+        }
+        MyList<Integer> allIndices = new MyLinkedList<>();
+        try {
+            for (int i = 0; i < futures.size(); i++) {
+                Future<MyList<Integer>> future = futures.get(i);
+                MyList<Integer> partialResult = future.get();
+
+                if (partialResult != null) {
+                    for (int j = 0; j < partialResult.size(); j++) {
+                        allIndices.add(partialResult.get(j));
+                    }
+                }
+            }
+        } catch (Exception e) {
+            throw new RuntimeException("Ошибка при поиске", e);
+        } finally {
+            executor.shutdown();
+        }
+
+        sortList(allIndices);
+
+        int[] resultArray = new int[allIndices.size()];
+        for (int i = 0; i < allIndices.size(); i++) {
+            resultArray[i] = allIndices.get(i);
+        }
+
+        return resultArray;
+    }
+
+    private void sortList(MyList<Integer> list) {
+        if (list.size() <= 1) return;
+
+        MyList<Integer> sorted = new MyLinkedList<>();
+
+        for (int i = 0; i < list.size(); i++) {
+            int value = list.get(i);
+            int insertIndex = 0;
+            while (insertIndex < sorted.size()) {
+                if (sorted.get(insertIndex) > value) {
+                    break;
+                }
+                insertIndex++;
+            }
+
+            MyList<Integer> temp = new MyLinkedList<>();
+            for (int k = 0; k < insertIndex; k++) {
+                temp.add(sorted.get(k));
+            }
+            temp.add(value);
+            for (int k = insertIndex; k < sorted.size(); k++) {
+                temp.add(sorted.get(k));
+            }
+            sorted = temp;
+        }
+
+        while (!list.isEmpty()) {
+            list.remove(0);
+        }
+
+        for (int i = 0; i < sorted.size(); i++) {
+            list.add(sorted.get(i));
+        }
+    }
+
+    private int calculateThreadCount(int size) {
+        int processors = Runtime.getRuntime().availableProcessors();
+        return Math.min(processors, size);
+    }
+
+    private int countChunkSize(int size, int threadCount) {
+        if (threadCount == 0) return 0;
+        return (size + threadCount - 1) / threadCount;
+    }
+
+    private MyList<Integer> findInRange(MyList<Student> students, Student target, int fromIndex, int toIndex) {
+        MyList<Integer> foundIndices = new MyLinkedList<>();
+
+        for (int i = fromIndex; i < toIndex; i++) {
+            Student current = students.get(i);
+            if (current != null && current.equals(target)) {
+                foundIndices.add(i);
+            }
+        }
+
+        return foundIndices;
+    }
+}
diff --git a/app/src/main/java/ru/project/search/AverageGradeRangeCriteria.java b/app/src/main/java/ru/project/search/AverageGradeRangeCriteria.java
new file mode 100644
index 0000000..a53a7c5
--- /dev/null
+++ b/app/src/main/java/ru/project/search/AverageGradeRangeCriteria.java
@@ -0,0 +1,22 @@
+package ru.project.search;
+
+import ru.project.student.Student;
+
+public class AverageGradeRangeCriteria implements StudentSearchCriteria {
+    private final double min;
+    private final double max;
+
+    public AverageGradeRangeCriteria(double min, double max) {
+        if (min > max) {
+            throw new IllegalArgumentException("Min grade must be <= max grade");
+        }
+        this.min = min;
+        this.max = max;
+    }
+
+    @Override
+    public boolean matches(Student student) {
+        double grade = student.getAverageGrade();
+        return grade >= min && grade <= max;
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/ru/project/search/CompositeStudentSearchCriteria.java b/app/src/main/java/ru/project/search/CompositeStudentSearchCriteria.java
new file mode 100644
index 0000000..063d087
--- /dev/null
+++ b/app/src/main/java/ru/project/search/CompositeStudentSearchCriteria.java
@@ -0,0 +1,51 @@
+package ru.project.search;
+
+import ru.project.student.Student;
+import java.util.ArrayList;
+import java.util.List;
+
+public class CompositeStudentSearchCriteria implements StudentSearchCriteria {
+    private final SearchOperation operation;
+    private final List<StudentSearchCriteria> criteriaList = new ArrayList<>();
+
+    public CompositeStudentSearchCriteria(SearchOperation operation) {
+        if (operation == null) {
+            throw new IllegalArgumentException("Operation must not be null");
+        }
+        this.operation = operation;
+    }
+
+    public void add(StudentSearchCriteria criteria) {
+        if (criteria == null) {
+            throw new IllegalArgumentException("Criteria must not be null");
+        }
+        criteriaList.add(criteria);
+    }
+
+    public void remove(StudentSearchCriteria criteria) {
+        criteriaList.remove(criteria);
+    }
+
+    @Override
+    public boolean matches(Student student) {
+        if (criteriaList.isEmpty()) {
+            return operation == SearchOperation.INTERSECTION;
+        }
+
+        if (operation == SearchOperation.UNION) {
+            for (StudentSearchCriteria c : criteriaList) {
+                if (c.matches(student)) {
+                    return true;
+                }
+            }
+            return false;
+        } else {
+            for (StudentSearchCriteria c : criteriaList) {
+                if (!c.matches(student)) {
+                    return false;
+                }
+            }
+            return true;
+        }
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/ru/project/search/GroupNumberRangeCriteria.java b/app/src/main/java/ru/project/search/GroupNumberRangeCriteria.java
new file mode 100644
index 0000000..61ea406
--- /dev/null
+++ b/app/src/main/java/ru/project/search/GroupNumberRangeCriteria.java
@@ -0,0 +1,25 @@
+package ru.project.search;
+
+import ru.project.student.Student;
+
+public class GroupNumberRangeCriteria implements StudentSearchCriteria {
+    private final String min;
+    private final String max;
+
+    public GroupNumberRangeCriteria(String min, String max) {
+        if (min == null || max == null) {
+            throw new IllegalArgumentException("Min and max must not be null");
+        }
+        if (min.compareTo(max) > 0) {
+            throw new IllegalArgumentException("Min group must be <= max group");
+        }
+        this.min = min;
+        this.max = max;
+    }
+
+    @Override
+    public boolean matches(Student student) {
+        String group = student.getGroupNumber();
+        return group.compareTo(min) >= 0 && group.compareTo(max) <= 0;
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/ru/project/search/RecordBookNumberRangeCriteria.java b/app/src/main/java/ru/project/search/RecordBookNumberRangeCriteria.java
new file mode 100644
index 0000000..41131b4
--- /dev/null
+++ b/app/src/main/java/ru/project/search/RecordBookNumberRangeCriteria.java
@@ -0,0 +1,22 @@
+package ru.project.search;
+
+import ru.project.student.Student;
+
+public class RecordBookNumberRangeCriteria implements StudentSearchCriteria {
+    private final int min;
+    private final int max;
+
+    public RecordBookNumberRangeCriteria(int min, int max) {
+        if (min > max) {
+            throw new IllegalArgumentException("Min record number must be <= max");
+        }
+        this.min = min;
+        this.max = max;
+    }
+
+    @Override
+    public boolean matches(Student student) {
+        int number = student.getRecordBookNumber();
+        return number >= min && number <= max;
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/ru/project/search/SearchOperation.java b/app/src/main/java/ru/project/search/SearchOperation.java
new file mode 100644
index 0000000..d616f97
--- /dev/null
+++ b/app/src/main/java/ru/project/search/SearchOperation.java
@@ -0,0 +1,6 @@
+package ru.project.search;
+
+public enum SearchOperation {
+    UNION,
+    INTERSECTION
+}
\ No newline at end of file
diff --git a/app/src/main/java/ru/project/search/StudentSearchCriteria.java b/app/src/main/java/ru/project/search/StudentSearchCriteria.java
new file mode 100644
index 0000000..f157982
--- /dev/null
+++ b/app/src/main/java/ru/project/search/StudentSearchCriteria.java
@@ -0,0 +1,7 @@
+package ru.project.search;
+
+import ru.project.student.Student;
+
+public interface StudentSearchCriteria {
+    boolean matches(Student student);
+}
\ No newline at end of file
diff --git a/app/src/main/java/ru/project/search/StudentSearchService.java b/app/src/main/java/ru/project/search/StudentSearchService.java
new file mode 100644
index 0000000..4ced3c9
--- /dev/null
+++ b/app/src/main/java/ru/project/search/StudentSearchService.java
@@ -0,0 +1,30 @@
+package ru.project.search;
+
+import ru.project.list.MyList;
+import ru.project.list.MyLinkedList;
+import ru.project.student.Student;
+
+public class StudentSearchService {
+    private final StudentSearchCriteria criteria;
+
+    public StudentSearchService(StudentSearchCriteria criteria) {
+        if (criteria == null) {
+            throw new IllegalArgumentException("Criteria must not be null");
+        }
+        this.criteria = criteria;
+    }
+
+    public MyList<Student> find(MyList<Student> students) {
+        if (students == null) {
+            return new MyLinkedList<>();
+        }
+        MyList<Student> result = new MyLinkedList<>();
+        for (int i = 0; i < students.size(); i++) {
+            Student s = students.get(i);
+            if (criteria.matches(s)) {
+                result.add(s);
+            }
+        }
+        return result;
+    }
+}
\ No newline at end of file
diff --git a/app/src/test/java/ru/project/MyListCollectorTest.java b/app/src/test/java/ru/project/MyListCollectorTest.java
new file mode 100644
index 0000000..6155d57
--- /dev/null
+++ b/app/src/test/java/ru/project/MyListCollectorTest.java
@@ -0,0 +1,63 @@
+package ru.test.maven.spring;
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.*;
+import java.util.Set;
+import java.util.stream.Collector;
+import java.util.stream.IntStream;
+import java.util.Collections;
+public class MyListCollectorTest
+{
+    private final MyListCollector<Integer> collector = new MyListCollector<>();
+
+    @Test
+    void shouldTestCollectInOrderSequential() {
+        MyList<Integer> result = IntStream.range(0, 10)
+                .boxed()
+                .collect(MyCollectors.toMyList());
+
+        assertEquals(10, result.size());
+        for (int i = 0; i < result.size(); i++) {
+            assertEquals(i, (int) result.get(i));
+        }
+
+    }
+
+    @Test
+    void shouldTestCollectInOrderParallel() {
+        MyList<Integer> result = IntStream.range(0, 100)
+                .parallel()
+                .boxed()
+                .collect(MyCollectors.toMyList());
+
+        assertEquals(100, result.size());
+        for (int i = 0; i < result.size(); i++) {
+            assertEquals(i, (int) result.get(i));
+        }
+    }
+
+    @Test
+    void shouldTestHandleEmptyStream() {
+        MyList<Integer> result = IntStream.empty()
+                .boxed()
+                .collect(MyCollectors.toMyList());
+
+        assertTrue(result.isEmpty());
+
+    }
+    @Test
+    void shouldTestNotUseStandardList() {
+        MyList<String> result = IntStream.range(0, 5)
+                .mapToObj(i -> "item" + i)
+                .collect(MyCollectors.toMyList());
+
+        assertInstanceOf(MyList.class, result);
+        assertFalse(result instanceof java.util.List);
+    }
+    @Test
+    void shouldTestHaveCorrectCharacteristics() {
+        Set<Collector.Characteristics> characteristics = collector.characteristics();
+        assertTrue(characteristics.contains(java.util.stream.Collector.Characteristics.IDENTITY_FINISH));
+        assertFalse(characteristics.contains(java.util.stream.Collector.Characteristics.UNORDERED));
+    }
+
+}
diff --git a/app/src/test/java/ru/project/collectors/MyListCollectorTest.java b/app/src/test/java/ru/project/collectors/MyListCollectorTest.java
new file mode 100644
index 0000000..3ca8d21
--- /dev/null
+++ b/app/src/test/java/ru/project/collectors/MyListCollectorTest.java
@@ -0,0 +1,64 @@
+package ru.test.maven.spring;
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.*;
+import java.util.Set;
+import java.util.stream.Collector;
+import java.util.stream.IntStream;
+import java.util.Collections;
+
+public class MyListCollectorTest
+{
+    private final MyListCollector<Integer> collector = new MyListCollector<>();
+
+    @Test
+    void shouldTestCollectInOrderSequential() {
+        MyList<Integer> result = IntStream.range(0, 10)
+                .boxed()
+                .collect(MyCollectors.toMyList());
+
+        assertEquals(10, result.size());
+        for (int i = 0; i < result.size(); i++) {
+            assertEquals(i, (int) result.get(i));
+        }
+
+    }
+
+    @Test
+    void shouldTestCollectInOrderParallel() {
+        MyList<Integer> result = IntStream.range(0, 100)
+                .parallel()
+                .boxed()
+                .collect(MyCollectors.toMyList());
+
+        assertEquals(100, result.size());
+        for (int i = 0; i < result.size(); i++) {
+            assertEquals(i, (int) result.get(i));
+        }
+    }
+
+    @Test
+    void shouldTestHandleEmptyStream() {
+        MyList<Integer> result = IntStream.empty()
+                .boxed()
+                .collect(MyCollectors.toMyList());
+
+        assertTrue(result.isEmpty());
+
+    }
+    @Test
+    void shouldTestNotUseStandardList() {
+        MyList<String> result = IntStream.range(0, 5)
+                .mapToObj(i -> "item" + i)
+                .collect(MyCollectors.toMyList());
+
+        assertInstanceOf(MyList.class, result);
+        assertFalse(result instanceof java.util.List);
+    }
+    @Test
+    void shouldTestHaveCorrectCharacteristics() {
+        Set<Collector.Characteristics> characteristics = collector.characteristics();
+        assertTrue(characteristics.contains(java.util.stream.Collector.Characteristics.IDENTITY_FINISH));
+        assertFalse(characteristics.contains(java.util.stream.Collector.Characteristics.UNORDERED));
+    }
+
+}
diff --git a/app/src/test/java/ru/project/finder/StudentOccurrenceIndexFinderTest.java b/app/src/test/java/ru/project/finder/StudentOccurrenceIndexFinderTest.java
new file mode 100644
index 0000000..b61ed58
--- /dev/null
+++ b/app/src/test/java/ru/project/finder/StudentOccurrenceIndexFinderTest.java
@@ -0,0 +1,134 @@
+package ru.project.finder;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class StudentOccurrenceIndexFinderTest
+{
+    private StudentOccurrenceIndexFinder finder;
+    private MyList<Student> students;
+
+    @BeforeEach
+    void setUp() {
+        finder = new StudentOccurrenceIndexFinder();
+        students = new MyLinkedList<>();
+    }
+
+    @Test
+    void shouldTesfindOccurrences_emptyList_returnsEmptyArray() {
+        int[] result = finder.findOccurrences(students, new Student("A12", 4.5, 1));
+        assertEquals(0, result.length);
+    }
+    @Test
+    void shouldTesfindOccurrences_noMatches_returnsEmptyArray() {
+        students.add(new Student("A12", 4.0, 101));
+        students.add(new Student("B23", 3.5, 102));
+        Student target = new Student("C34", 4.8, 103); // такого нет
+
+        int[] result = finder.findOccurrences(students, target);
+        assertEquals(0, result.length);
+    }
+    @Test
+    void shouldTesfindOccurrences_singleMatch_returnsCorrectIndex() {
+        students.add(new Student("A12", 4.0, 101));
+        students.add(new Student("B23", 3.5, 102)); // target здесь
+        students.add(new Student("C34", 4.8, 103));
+
+        Student target = new Student("B23", 3.5, 102);
+        int[] result = finder.findOccurrences(students, target);
+
+        assertEquals(1, result.length);
+        assertEquals(1, result[0]);
+    }
+    @Test
+    void shouldTesfindOccurrences_multipleMatches_returnsAllIndicesSorted() {
+        // индексы: 0, 2, 4 — должны вернуться в порядке возрастания
+        students.add(new Student("A12", 4.5, 101)); // match
+        students.add(new Student("B23", 3.8, 102));
+        students.add(new Student("A12", 4.5, 101)); // match
+        students.add(new Student("C34", 4.0, 103));
+        students.add(new Student("A12", 4.5, 101)); // match
+
+        Student target = new Student("A12", 4.5, 101);
+        int[] result = finder.findOccurrences(students, target);
+
+        assertEquals(3, result.length);
+        assertArrayEquals(new int[]{0, 2, 4}, result);
+    }
+
+    @Test
+    void shouldTesfindOccurrences_allElementsMatch_returnsAllIndices() {
+        Student s = new Student("X99", 5.0, 999);
+        students.add(s);
+        students.add(s);
+        students.add(s);
+
+        int[] result = finder.findOccurrences(students, s);
+        assertEquals(3, result.length);
+        assertArrayEquals(new int[]{0, 1, 2}, result);
+    }
+
+    @Test
+    void shouldTesfindOccurrences_differentAverageGrade_noMatch() {
+        students.add(new Student("A12", 4.50, 101));
+        Student target = new Student("A12", 4.51, 101); // отличается балл
+
+        int[] result = finder.findOccurrences(students, target);
+        assertEquals(0, result.length);
+    }
+
+    @Test
+    void shouldTesfindOccurrences_differentGroupNumber_noMatch() {
+        students.add(new Student("A12", 4.5, 101));
+        Student target = new Student("B12", 4.5, 101); // другая группа
+
+        int[] result = finder.findOccurrences(students, target);
+        assertEquals(0, result.length);
+    }
+
+    @Test
+    void shouldTesfindOccurrences_differentRecordBookNumber_noMatch() {
+        students.add(new Student("A12", 4.5, 101));
+        Student target = new Student("A12", 4.5, 102); // другой номер зачетки
+
+        int[] result = finder.findOccurrences(students, target);
+        assertEquals(0, result.length);
+    }
+
+
+    @Test
+    void shouldTesfindOccurrences_nullList_throwsException() {
+        Student target = new Student("A12", 4.5, 101);
+        assertThrows(IllegalArgumentException.class, () -> finder.findOccurrences(null, target));
+    }
+
+
+    @Test
+    void shouldTesfindOccurrences_nullTarget_throwsException() {
+        assertThrows(IllegalArgumentException.class, () -> finder.findOccurrences(students, null));
+    }
+    @Test
+    void shouldTesfindOccurrences_resultIsSorted() {
+        String[] validGroups = {"A00", "A01", "B12", "C99", "X55"};
+
+        for (int i = 0; i < 50; i++) {
+            String group = validGroups[i % validGroups.length];
+            double grade = (3.0 + (i % 3)) / 2.0;
+            if (i % 3 == 0) {
+
+                students.add(new Student("A12", 4.5, 101));
+            } else {
+                students.add(new Student(group, grade, 200 + i));
+            }
+        }
+        Student target = new Student("A12", 4.5, 101);
+        int[] result = finder.findOccurrences(students, target);
+
+
+        for (int i = 1; i < result.length; i++) {
+            assertTrue(result[i] > result[i - 1], "Результат должен быть отсортирован");
+        }
+    }
+}
diff --git a/app/src/test/java/ru/project/search/StudentSearchTest.java b/app/src/test/java/ru/project/search/StudentSearchTest.java
new file mode 100644
index 0000000..d12bd9c
--- /dev/null
+++ b/app/src/test/java/ru/project/search/StudentSearchTest.java
@@ -0,0 +1,314 @@
+package ru.project.search;
+
+import org.junit.jupiter.api.Test;
+import ru.project.list.MyList;
+import ru.project.list.MyLinkedList;
+import ru.project.student.Student;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class StudentSearchTest {
+
+    @Test
+    void testGroupNumberRangeMatchesInside() {
+        StudentSearchCriteria criteria = new GroupNumberRangeCriteria("A10", "C30");
+        Student student = new Student("B20", 4.5, 123);
+        assertTrue(criteria.matches(student));
+    }
+
+    @Test
+    void testGroupNumberRangeMatchesLowerBoundary() {
+        StudentSearchCriteria criteria = new GroupNumberRangeCriteria("A10", "C30");
+        Student student = new Student("A10", 4.5, 123);
+        assertTrue(criteria.matches(student));
+    }
+
+    @Test
+    void testGroupNumberRangeMatchesUpperBoundary() {
+        StudentSearchCriteria criteria = new GroupNumberRangeCriteria("A10", "C30");
+        Student student = new Student("C30", 4.5, 123);
+        assertTrue(criteria.matches(student));
+    }
+
+    @Test
+    void testGroupNumberRangeDoesNotMatchOutside() {
+        StudentSearchCriteria criteria = new GroupNumberRangeCriteria("A10", "C30");
+        Student student = new Student("D00", 4.5, 123);
+        assertFalse(criteria.matches(student));
+    }
+
+    @Test
+    void testGroupNumberRangeInvalidMinMaxThrowsException() {
+        assertThrows(IllegalArgumentException.class,
+                () -> new GroupNumberRangeCriteria("C30", "A10"));
+    }
+
+    @Test
+    void testGroupNumberRangeNullValuesThrowsException() {
+        assertThrows(IllegalArgumentException.class,
+                () -> new GroupNumberRangeCriteria(null, "A10"));
+        assertThrows(IllegalArgumentException.class,
+                () -> new GroupNumberRangeCriteria("A10", null));
+    }
+
+    @Test
+    void testAverageGradeRangeMatchesInside() {
+        StudentSearchCriteria criteria = new AverageGradeRangeCriteria(4.0, 5.0);
+        Student student = new Student("A12", 4.5, 123);
+        assertTrue(criteria.matches(student));
+    }
+
+    @Test
+    void testAverageGradeRangeMatchesLowerBoundary() {
+        StudentSearchCriteria criteria = new AverageGradeRangeCriteria(4.0, 5.0);
+        Student student = new Student("A12", 4.0, 123);
+        assertTrue(criteria.matches(student));
+    }
+
+    @Test
+    void testAverageGradeRangeMatchesUpperBoundary() {
+        StudentSearchCriteria criteria = new AverageGradeRangeCriteria(4.0, 5.0);
+        Student student = new Student("A12", 5.0, 123);
+        assertTrue(criteria.matches(student));
+    }
+
+    @Test
+    void testAverageGradeRangeDoesNotMatchBelow() {
+        StudentSearchCriteria criteria = new AverageGradeRangeCriteria(4.0, 5.0);
+        Student student = new Student("A12", 3.9, 123);
+        assertFalse(criteria.matches(student));
+    }
+
+    @Test
+    void testAverageGradeRangeDoesNotMatchAbove() {
+        StudentSearchCriteria criteria = new AverageGradeRangeCriteria(4.0, 5.0);
+        Student student = new Student("A12", 5.1, 123);
+        assertFalse(criteria.matches(student));
+    }
+
+    @Test
+    void testAverageGradeRangeInvalidMinMaxThrowsException() {
+        assertThrows(IllegalArgumentException.class,
+                () -> new AverageGradeRangeCriteria(5.0, 4.0));
+    }
+
+    @Test
+    void testRecordBookNumberRangeMatchesInside() {
+        StudentSearchCriteria criteria = new RecordBookNumberRangeCriteria(100, 200);
+        Student student = new Student("A12", 4.5, 150);
+        assertTrue(criteria.matches(student));
+    }
+
+    @Test
+    void testRecordBookNumberRangeMatchesLowerBoundary() {
+        StudentSearchCriteria criteria = new RecordBookNumberRangeCriteria(100, 200);
+        Student student = new Student("A12", 4.5, 100);
+        assertTrue(criteria.matches(student));
+    }
+
+    @Test
+    void testRecordBookNumberRangeMatchesUpperBoundary() {
+        StudentSearchCriteria criteria = new RecordBookNumberRangeCriteria(100, 200);
+        Student student = new Student("A12", 4.5, 200);
+        assertTrue(criteria.matches(student));
+    }
+
+    @Test
+    void testRecordBookNumberRangeDoesNotMatchBelow() {
+        StudentSearchCriteria criteria = new RecordBookNumberRangeCriteria(100, 200);
+        Student student = new Student("A12", 4.5, 99);
+        assertFalse(criteria.matches(student));
+    }
+
+    @Test
+    void testRecordBookNumberRangeDoesNotMatchAbove() {
+        StudentSearchCriteria criteria = new RecordBookNumberRangeCriteria(100, 200);
+        Student student = new Student("A12", 4.5, 201);
+        assertFalse(criteria.matches(student));
+    }
+
+    @Test
+    void testRecordBookNumberRangeInvalidMinMaxThrowsException() {
+        assertThrows(IllegalArgumentException.class,
+                () -> new RecordBookNumberRangeCriteria(200, 100));
+    }
+
+    @Test
+    void testCompositeIntersectionEmptyReturnsTrue() {
+        CompositeStudentSearchCriteria composite = new CompositeStudentSearchCriteria(SearchOperation.INTERSECTION);
+        Student student = new Student("A12", 4.5, 123);
+        assertTrue(composite.matches(student));
+    }
+
+    @Test
+    void testCompositeUnionEmptyReturnsFalse() {
+        CompositeStudentSearchCriteria composite = new CompositeStudentSearchCriteria(SearchOperation.UNION);
+        Student student = new Student("A12", 4.5, 123);
+        assertFalse(composite.matches(student));
+    }
+
+    @Test
+    void testCompositeIntersectionAllTrue() {
+        CompositeStudentSearchCriteria composite = new CompositeStudentSearchCriteria(SearchOperation.INTERSECTION);
+        composite.add(new GroupNumberRangeCriteria("A10", "C30"));
+        composite.add(new AverageGradeRangeCriteria(4.0, 5.0));
+        Student student = new Student("B20", 4.5, 123);
+        assertTrue(composite.matches(student));
+    }
+
+    @Test
+    void testCompositeIntersectionOneFalse() {
+        CompositeStudentSearchCriteria composite = new CompositeStudentSearchCriteria(SearchOperation.INTERSECTION);
+        composite.add(new GroupNumberRangeCriteria("A10", "C30"));
+        composite.add(new AverageGradeRangeCriteria(4.0, 5.0));
+        Student student = new Student("B20", 3.5, 123);
+        assertFalse(composite.matches(student));
+    }
+
+    @Test
+    void testCompositeUnionOneTrue() {
+        CompositeStudentSearchCriteria composite = new CompositeStudentSearchCriteria(SearchOperation.UNION);
+        composite.add(new GroupNumberRangeCriteria("A10", "C30"));
+        composite.add(new AverageGradeRangeCriteria(4.0, 5.0));
+        Student student = new Student("D00", 4.5, 123);
+        assertTrue(composite.matches(student));
+    }
+
+    @Test
+    void testCompositeUnionAllFalse() {
+        CompositeStudentSearchCriteria composite = new CompositeStudentSearchCriteria(SearchOperation.UNION);
+        composite.add(new GroupNumberRangeCriteria("A10", "C30"));
+        composite.add(new AverageGradeRangeCriteria(4.0, 5.0));
+        Student student = new Student("D00", 3.5, 123);
+        assertFalse(composite.matches(student));
+    }
+
+    @Test
+    void testCompositeWithNestedComposite() {
+        CompositeStudentSearchCriteria outer = new CompositeStudentSearchCriteria(SearchOperation.INTERSECTION);
+        outer.add(new GroupNumberRangeCriteria("A10", "C30"));
+
+        CompositeStudentSearchCriteria inner = new CompositeStudentSearchCriteria(SearchOperation.UNION);
+        inner.add(new AverageGradeRangeCriteria(4.0, 5.0));
+        inner.add(new RecordBookNumberRangeCriteria(100, 200));
+
+        outer.add(inner);
+
+        Student student = new Student("B20", 4.5, 150);
+        assertTrue(outer.matches(student));
+        student = new Student("B20", 3.5, 150);
+        assertFalse(outer.matches(student));
+        student = new Student("D00", 4.5, 150);
+        assertFalse(outer.matches(student));
+    }
+
+    @Test
+    void testSearchServiceWithSingleCriteria() {
+        MyList<Student> students = new MyLinkedList<>();
+        students.add(new Student("A10", 4.5, 1));
+        students.add(new Student("B20", 3.8, 2));
+        students.add(new Student("C30", 4.9, 3));
+
+        StudentSearchCriteria criteria = new AverageGradeRangeCriteria(4.0, 5.0);
+        StudentSearchService service = new StudentSearchService(criteria);
+        MyList<Student> result = service.find(students);
+
+        assertEquals(2, result.size());
+        assertEquals("A10", result.get(0).getGroupNumber());
+        assertEquals("C30", result.get(1).getGroupNumber());
+    }
+
+    @Test
+    void testSearchServiceEmptyResult() {
+        MyList<Student> students = new MyLinkedList<>();
+        students.add(new Student("A10", 3.5, 1));
+        students.add(new Student("B20", 3.8, 2));
+
+        StudentSearchCriteria criteria = new AverageGradeRangeCriteria(4.0, 5.0);
+        StudentSearchService service = new StudentSearchService(criteria);
+        MyList<Student> result = service.find(students);
+
+        assertEquals(0, result.size());
+    }
+
+    @Test
+    void testSearchServiceEmptyCollection() {
+        MyList<Student> students = new MyLinkedList<>();
+        StudentSearchCriteria criteria = new AverageGradeRangeCriteria(4.0, 5.0);
+        StudentSearchService service = new StudentSearchService(criteria);
+        MyList<Student> result = service.find(students);
+        assertEquals(0, result.size());
+    }
+
+    @Test
+    void testSearchServicePreservesOrder() {
+        MyList<Student> students = new MyLinkedList<>();
+        students.add(new Student("Z00", 4.5, 1));
+        students.add(new Student("A10", 4.5, 2));
+        students.add(new Student("M30", 4.5, 3));
+
+        StudentSearchCriteria criteria = new AverageGradeRangeCriteria(4.0, 5.0);
+        StudentSearchService service = new StudentSearchService(criteria);
+        MyList<Student> result = service.find(students);
+
+        assertEquals(3, result.size());
+        assertEquals("Z00", result.get(0).getGroupNumber());
+        assertEquals("A10", result.get(1).getGroupNumber());
+        assertEquals("M30", result.get(2).getGroupNumber());
+    }
+
+    @Test
+    void testSearchServiceDoesNotModifyOriginal() {
+        MyList<Student> original = new MyLinkedList<>();
+        original.add(new Student("A10", 4.5, 1));
+        original.add(new Student("B20", 3.8, 2));
+
+        MyList<Student> copy = new MyLinkedList<>();
+        for (int i = 0; i < original.size(); i++) {
+            copy.add(original.get(i));
+        }
+
+        StudentSearchCriteria criteria = new AverageGradeRangeCriteria(4.0, 5.0);
+        StudentSearchService service = new StudentSearchService(criteria);
+        service.find(original);
+
+        assertEquals(copy.size(), original.size());
+        for (int i = 0; i < copy.size(); i++) {
+            assertEquals(copy.get(i).getGroupNumber(), original.get(i).getGroupNumber());
+        }
+    }
+
+    @Test
+    void testSearchServiceWithNullCriteriaThrowsException() {
+        assertThrows(IllegalArgumentException.class,
+                () -> new StudentSearchService(null));
+    }
+
+    @Test
+    void testSearchServiceWithCompositeCriteria() {
+        MyList<Student> students = new MyLinkedList<>();
+        students.add(new Student("A10", 4.5, 1));
+        students.add(new Student("B20", 4.5, 2));
+        students.add(new Student("C30", 3.5, 3));
+
+        CompositeStudentSearchCriteria composite = new CompositeStudentSearchCriteria(SearchOperation.INTERSECTION);
+        composite.add(new GroupNumberRangeCriteria("A10", "B20"));
+        composite.add(new AverageGradeRangeCriteria(4.0, 5.0));
+
+        StudentSearchService service = new StudentSearchService(composite);
+        MyList<Student> result = service.find(students);
+
+        assertEquals(2, result.size());
+        assertEquals("A10", result.get(0).getGroupNumber());
+        assertEquals("B20", result.get(1).getGroupNumber());
+    }
+
+    @Test
+    void testSearchServiceWithNullStudentListReturnsEmpty() {
+        StudentSearchCriteria criteria = new AverageGradeRangeCriteria(4.0, 5.0);
+        StudentSearchService service = new StudentSearchService(criteria);
+        MyList<Student> result = service.find(null);
+        assertNotNull(result);
+        assertEquals(0, result.size());
+    }
+}
\ No newline at end of file
diff --git a/docs/tasks/RandomStudentGenerator.md b/docs/tasks/RandomStudentGenerator.md
new file mode 100644
index 0000000..3e902f9
--- /dev/null
+++ b/docs/tasks/RandomStudentGenerator.md
@@ -0,0 +1,305 @@
+# Техническое задание: генератор случайных студентов
+
+## Задача
+
+Реализовать класс для формирования `MyList<Student>` со случайными значениями.
+
+По умолчанию ограничения диапазона для генерации не задаются. В таком случае значения должны генерироваться во всём допустимом диапазоне, установленном правилами класса `Student`.
+
+Генерация объектов должна выполняться через существующий `StudentBuilder`.
+
+## Название класса
+
+```text id="m9s0q1"
+RandomStudentGenerator
+```
+
+## Контракт класса
+
+Класс должен хранить текущие ограничения генерации для каждого поля `Student`.
+
+Для каждого поля необходимо предоставить по два метода: левое и правое ограничение.
+
+### `groupNumber`
+
+Тип поля: `String`.
+
+```java id="t2z8k4"
+RandomStudentGenerator setMinGroupNumber(String minGroupNumber);
+```
+
+```java id="q7x5n1"
+RandomStudentGenerator setMaxGroupNumber(String maxGroupNumber);
+```
+
+Ограничения применяются при генерации `groupNumber`.
+
+Сравнение границ выполнять в соответствии с правилами, используемыми для `groupNumber` в `Student`.
+
+### `averageGrade`
+
+Тип поля: `double`.
+
+```java id="v4n2j8"
+RandomStudentGenerator setMinAverageGrade(double minAverageGrade);
+```
+
+```java id="r5c1p9"
+RandomStudentGenerator setMaxAverageGrade(double maxAverageGrade);
+```
+
+Диапазон должен быть включительным:
+
+```text id="u3k7w2"
+minAverageGrade <= averageGrade <= maxAverageGrade
+```
+
+### `recordBookNumber`
+
+Тип поля: `int`.
+
+```java id="d8m4x6"
+RandomStudentGenerator setMinRecordBookNumber(int minRecordBookNumber);
+```
+
+```java id="e1q9s5"
+RandomStudentGenerator setMaxRecordBookNumber(int maxRecordBookNumber);
+```
+
+Диапазон должен быть включительным:
+
+```text id="y6p2v8"
+minRecordBookNumber <= recordBookNumber <= maxRecordBookNumber
+```
+
+## Метод генерации
+
+Основной метод:
+
+```java id="k3w7m1"
+MyList<Student> generate(int size);
+```
+
+Контракт:
+
+- создаёт ровно `size` объектов `Student`;
+- все объекты должны быть валидными;
+- каждый объект создаётся через `StudentBuilder`;
+- результат возвращается как `MyList<Student>`;
+- стандартные `List`, `ArrayList`, `LinkedList` и другие контейнеры использовать нельзя.
+
+## Поведение диапазонов по умолчанию
+
+Если для поля ограничение не задано, используется весь допустимый диапазон этого поля.
+
+Необходимо учитывать существующие ограничения `Student`, в частности:
+
+```text id="z4r8t2"
+averageGrade:
+getMinAverageGrade()
+getMaxAverageGrade()
+
+recordBookNumber:
+getMinRecordBookNumber()
+```
+
+Для `groupNumber` использовать существующий шаблон:
+
+```text id="n5c7y3"
+getGroupNumberPattern()
+```
+
+Генерируемое значение `groupNumber` должно соответствовать требованиям `Student`.
+
+## Проверка ограничений
+
+При установке границ необходимо проверять их корректность.
+
+Недопустимые случаи:
+
+```text id="h2k6p4"
+min > max
+```
+
+Для них выбрасывать:
+
+```java id="c7v3n9"
+IllegalArgumentException
+```
+
+Ограничение также не должно выходить за допустимые значения `Student`.
+
+## Рекомендуемая реализация
+
+Класс должен хранить шесть ограничений:
+
+```text id="b5q9x2"
+minGroupNumber
+maxGroupNumber
+
+minAverageGrade
+maxAverageGrade
+
+minRecordBookNumber
+maxRecordBookNumber
+```
+
+Для каждого поля значения генерируются независимо.
+
+Рекомендуется использовать стандартный генератор случайных чисел Java, например:
+
+```java id="a8f4k1"
+Random
+```
+
+или:
+
+```java id="p3m7d5"
+ThreadLocalRandom
+```
+
+При создании `Student`:
+
+```text id="w6j2r9"
+сгенерировать поля
+        ↓
+StudentBuilder
+        ↓
+build()
+        ↓
+Student
+        ↓
+MyList<Student>
+```
+
+Дополнительную валидацию, дублирующую правила `Student`, в генераторе не реализовывать.
+
+## Примеры использования
+
+Без настройки диапазонов:
+
+```java id="s2k8m4"
+RandomStudentGenerator generator =
+        new RandomStudentGenerator();
+
+MyList<Student> students =
+        generator.generate(100);
+```
+
+С настройкой диапазонов:
+
+```java id="f7q3n1"
+RandomStudentGenerator generator =
+        new RandomStudentGenerator()
+                .setMinGroupNumber("A00")
+                .setMaxGroupNumber("Z99")
+                .setMinAverageGrade(3.0)
+                .setMaxAverageGrade(5.0)
+                .setMinRecordBookNumber(10000)
+                .setMaxRecordBookNumber(99999);
+
+MyList<Student> students =
+        generator.generate(100);
+```
+
+## Тесты
+
+### Генерация без ограничений
+
+```java id="r1w5p8"
+MyList<Student> result = generator.generate(100);
+```
+
+Проверить:
+
+- размер равен `100`;
+- все элементы не равны `null`;
+- каждый `Student` валиден.
+
+### Ограничение `averageGrade`
+
+Задать:
+
+```text id="x4n7k2"
+3.0 — 4.0
+```
+
+Проверить, что все значения находятся в указанном диапазоне.
+
+### Ограничение `recordBookNumber`
+
+Задать:
+
+```text id="q9m3v6"
+10000 — 20000
+```
+
+Проверить диапазон и включение границ.
+
+### Ограничение `groupNumber`
+
+Задать левую и правую границы.
+
+Проверить, что все сгенерированные значения находятся между ними согласно правилам сравнения `groupNumber`.
+
+### Граничные значения
+
+Установить:
+
+```text id="p8c4s1"
+min == max
+```
+
+Проверить, что все сгенерированные значения равны указанной границе.
+
+### Некорректный диапазон
+
+Проверить выброс `IllegalArgumentException`, если:
+
+```text id="z6t2h5"
+min > max
+```
+
+### Некорректное ограничение
+
+Передать диапазон, выходящий за допустимые значения `Student`.
+
+Проверить выброс исключения.
+
+### Генерация пустой коллекции
+
+Для:
+
+```java id="j5r8w3"
+generate(0)
+```
+
+ожидается пустой `MyList<Student>`.
+
+### Некорректный размер
+
+Для отрицательного размера:
+
+```java id="n2k7p4"
+generate(-1)
+```
+
+ожидается `IllegalArgumentException`.
+
+## Результат
+
+Необходимо реализовать:
+
+```text id="v8m3q6"
+RandomStudentGenerator.java
+```
+
+Класс должен использовать существующие:
+
+```text id="f1j9x4"
+Student.java
+StudentBuilder.java
+MyList.java
+```
+
+Изменять интерфейсы `Student`, `StudentBuilder` и `MyList` для выполнения данного задания не требуется.