diff --git a/app/src/main/java/ru/project/student/Student.java b/app/src/main/java/ru/project/student/Student.java
new file mode 100644
index 0000000..b5d64d2
--- /dev/null
+++ b/app/src/main/java/ru/project/student/Student.java
@@ -0,0 +1,96 @@
+package ru.project.student;
+
+import java.util.Objects;
+
+public class Student {
+
+    public static final double MIN_AVERAGE_GRADE = 0.0;
+    public static final double MAX_AVERAGE_GRADE = 5.0;
+    public static final int MIN_RECORD_BOOK_NUMBER = 1;
+    public static final String GROUP_NUMBER_PATTERN = "^[A-Z][0-9]{2}$";
+
+    private final String groupNumber;
+    private final double averageGrade;
+    private final int recordBookNumber;
+
+    public Student(String groupNumber, double averageGrade, int recordBookNumber) {
+        if (groupNumber == null || !groupNumber.matches(GROUP_NUMBER_PATTERN)) {
+            throw new IllegalArgumentException(
+                    "Group number must match pattern: " + GROUP_NUMBER_PATTERN);
+        }
+        if (averageGrade < MIN_AVERAGE_GRADE || averageGrade > MAX_AVERAGE_GRADE) {
+            throw new IllegalArgumentException(
+                    "Average grade must be between " + MIN_AVERAGE_GRADE + " and " + MAX_AVERAGE_GRADE);
+        }
+        if (recordBookNumber < MIN_RECORD_BOOK_NUMBER) {
+            throw new IllegalArgumentException(
+                    "Record book number must be at least " + MIN_RECORD_BOOK_NUMBER);
+        }
+        this.groupNumber = groupNumber;
+        this.averageGrade = averageGrade;
+        this.recordBookNumber = recordBookNumber;
+    }
+
+    public String getGroupNumber() {
+        return groupNumber;
+    }
+
+    public double getAverageGrade() {
+        return averageGrade;
+    }
+
+    public int getRecordBookNumber() {
+        return recordBookNumber;
+    }
+
+    public Student withGroupNumber(String groupNumber) {
+        return new Student(groupNumber, this.averageGrade, this.recordBookNumber);
+    }
+
+    public Student withAverageGrade(double averageGrade) {
+        return new Student(this.groupNumber, averageGrade, this.recordBookNumber);
+    }
+
+    public Student withRecordBookNumber(int recordBookNumber) {
+        return new Student(this.groupNumber, this.averageGrade, recordBookNumber);
+    }
+
+    public static double getMaxAverageGrade() {
+        return MAX_AVERAGE_GRADE;
+    }
+
+    public static int getMinRecordBookNumber() {
+        return MIN_RECORD_BOOK_NUMBER;
+    }
+
+    public static String getGroupNumberPattern() {
+        return GROUP_NUMBER_PATTERN;
+    }
+
+    public String toString() {
+        return "Student{" +
+                "groupNumber='" + groupNumber + '\'' +
+                ", averageGrade=" + averageGrade +
+                ", recordBookNumber=" + recordBookNumber +
+                '}';
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null || getClass() != obj.getClass()) {
+            return false;
+        }
+        Student student = (Student) obj;
+        return Double.compare(averageGrade, student.averageGrade) == 0
+                && recordBookNumber == student.recordBookNumber
+                && Objects.equals(groupNumber, student.groupNumber);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(groupNumber, averageGrade, recordBookNumber);
+    }
+}
diff --git a/app/src/main/java/ru/project/student/StudentBuilder.java b/app/src/main/java/ru/project/student/StudentBuilder.java
new file mode 100644
index 0000000..6d7d5fc
--- /dev/null
+++ b/app/src/main/java/ru/project/student/StudentBuilder.java
@@ -0,0 +1,26 @@
+package ru.project.student;
+
+public class StudentBuilder {
+    private String groupNumber;
+    private double averageGrade;
+    private int recordBookNumber;
+
+    public StudentBuilder setGroupNumber(String groupNumber) {
+        this.groupNumber = groupNumber;
+        return this;
+    }
+
+    public StudentBuilder setAverageGrade(double averageGrade) {
+        this.averageGrade = averageGrade;
+        return this;
+    }
+
+    public StudentBuilder setRecordBookNumber(int recordBookNumber) {
+        this.recordBookNumber = recordBookNumber;
+        return this;
+    }
+
+    public Student build() {
+        return new Student(groupNumber, averageGrade, recordBookNumber);
+    }
+}
diff --git a/app/src/test/java/ru/project/student/StudentTest.java b/app/src/test/java/ru/project/student/StudentTest.java
new file mode 100644
index 0000000..09cf2e7
--- /dev/null
+++ b/app/src/test/java/ru/project/student/StudentTest.java
@@ -0,0 +1,145 @@
+package ru.project.student;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotSame;
+
+
+class StudentTest {
+
+    @Test
+    void testValidStudentCreation() {
+        Student student = new Student("A12", 4.5, 12345);
+        assertEquals("A12", student.getGroupNumber());
+        assertEquals(4.5, student.getAverageGrade());
+        assertEquals(12345, student.getRecordBookNumber());
+    }
+
+    @Test
+    void testValidGroupNumbers() {
+        assertDoesNotThrow(() -> new Student("A12", 4.5, 1));
+        assertDoesNotThrow(() -> new Student("B32", 4.5, 1));
+        assertDoesNotThrow(() -> new Student("Z00", 4.5, 1));
+    }
+
+    @Test
+    void testInvalidGroupNumbers() {
+        assertThrows(IllegalArgumentException.class, () -> new Student("a12", 4.5, 1));
+        assertThrows(IllegalArgumentException.class, () -> new Student("A1", 4.5, 1));
+        assertThrows(IllegalArgumentException.class, () -> new Student("A123", 4.5, 1));
+        assertThrows(IllegalArgumentException.class, () -> new Student("AA1", 4.5, 1));
+        assertThrows(IllegalArgumentException.class, () -> new Student("а1А", 4.5, 1));
+        assertThrows(IllegalArgumentException.class, () -> new Student("аа!!а123", 4.5, 1));
+        assertThrows(IllegalArgumentException.class, () -> new Student("23фи!12", 4.5, 1));
+        assertThrows(IllegalArgumentException.class, () -> new Student("№№###*()", 4.5, 1));
+    }
+
+    @Test
+    void testValidAverageGrades() {
+        assertDoesNotThrow(() -> new Student("A12", 0.0, 1));
+        assertDoesNotThrow(() -> new Student("A12", 5.0, 1));
+    }
+
+    @Test
+    void testInvalidAverageGrades() {
+        assertThrows(IllegalArgumentException.class, () -> new Student("A12", -1.0, 1));
+        assertThrows(IllegalArgumentException.class, () -> new Student("A12", 6.0, 1));
+    }
+
+    @Test
+    void testValidRecordBookNumbers() {
+        assertDoesNotThrow(() -> new Student("A12", 4.5, 1));
+        assertDoesNotThrow(() -> new Student("A12", 4.5, 12345));
+    }
+
+    @Test
+    void testInvalidRecordBookNumbers() {
+        assertThrows(IllegalArgumentException.class, () -> new Student("A12", 4.5, 0));
+        assertThrows(IllegalArgumentException.class, () -> new Student("A12", 4.5, -1));
+    }
+
+    @Test
+    void testWithGroupNumber() {
+        Student original = new Student("A12", 4.5, 12345);
+        Student updated = original.withGroupNumber("B32");
+
+        assertNotSame(original, updated);
+        assertEquals("B32", updated.getGroupNumber());
+        assertEquals(4.5, updated.getAverageGrade());
+        assertEquals(12345, updated.getRecordBookNumber());
+
+        assertEquals("A12", original.getGroupNumber());
+    }
+
+    @Test
+    void testWithAverageGrade() {
+        Student original = new Student("A12", 4.5, 12345);
+        Student updated = original.withAverageGrade(4.8);
+
+        assertNotSame(original, updated);
+        assertEquals(4.8, updated.getAverageGrade());
+        assertEquals("A12", updated.getGroupNumber());
+        assertEquals(12345, updated.getRecordBookNumber());
+
+        assertEquals(4.5, original.getAverageGrade());
+    }
+
+    @Test
+    void testWithRecordBookNumber() {
+        Student original = new Student("A12", 4.5, 12345);
+        Student updated = original.withRecordBookNumber(99999);
+
+        assertNotSame(original, updated);
+        assertEquals(99999, updated.getRecordBookNumber());
+        assertEquals("A12", updated.getGroupNumber());
+        assertEquals(4.5, updated.getAverageGrade());
+
+        assertEquals(12345, original.getRecordBookNumber());
+    }
+
+    @Test
+    void testWithInvalidGroupNumber() {
+        Student original = new Student("A12", 4.5, 12345);
+        assertThrows(IllegalArgumentException.class,
+                () -> original.withGroupNumber("a12"));
+        assertEquals("A12", original.getGroupNumber()); // не изменился
+    }
+
+    @Test
+    void testWithInvalidAverageGrade() {
+        Student original = new Student("A12", 4.5, 12345);
+        assertThrows(IllegalArgumentException.class,
+                () -> original.withAverageGrade(6.0));
+        assertEquals(4.5, original.getAverageGrade());
+    }
+
+    @Test
+    void testWithInvalidRecordBookNumber() {
+        Student original = new Student("A12", 4.5, 12345);
+        assertThrows(IllegalArgumentException.class,
+                () -> original.withRecordBookNumber(0));
+        assertEquals(12345, original.getRecordBookNumber());
+    }
+
+    @Test
+    void testEqualsAndHashCode() {
+        Student s1 = new Student("A12", 4.5, 12345);
+        Student s2 = new Student("A12", 4.5, 12345);
+        Student s3 = new Student("B32", 4.5, 12345);
+        Student s4 = new Student("A12", 4.8, 12345);
+        Student s5 = new Student("A12", 4.5, 99999);
+
+        assertEquals(s1, s2);
+        assertEquals(s1.hashCode(), s2.hashCode());
+
+        assertNotEquals(s1, s3);
+        assertNotEquals(s1, s4);
+        assertNotEquals(s1, s5);
+        assertNotEquals(s1, null);
+        assertNotEquals(s1, "some string");
+    }
+}