diff --git a/src/main/java/ru/lionarius/IntegralCalculator.java b/src/main/java/ru/lionarius/IntegralCalculator.java
index b1f1243..6841359 100644
--- a/src/main/java/ru/lionarius/IntegralCalculator.java
+++ b/src/main/java/ru/lionarius/IntegralCalculator.java
@@ -1,8 +1,11 @@
 package ru.lionarius;
 
+import ru.lionarius.sync.MyCountDownLatch;
+import ru.lionarius.sync.MyReentrantLock;
+import ru.lionarius.sync.MySemaphore;
+
 import java.util.ArrayList;
 import java.util.concurrent.*;
-import java.util.concurrent.locks.ReentrantLock;
 import java.util.function.BiConsumer;
 import java.util.function.Function;
 
@@ -111,9 +114,9 @@ public class IntegralCalculator {
         var sum = (function.apply(lowerBound) + function.apply(upperBound)) / 2;
 
         final var futures = new ArrayList<Future<Double>>();
-        final var semaphore = new Semaphore(2);
-        final var lock = new ReentrantLock();
-        final var latch = new CountDownLatch(parallelism);
+        final var semaphore = new MySemaphore(2);
+        final var lock = new MyReentrantLock();
+        final var latch = new MyCountDownLatch(parallelism);
 
         var times = new long[parallelism];
         var totalProgress = new long[]{0L};
diff --git a/src/main/java/ru/lionarius/sync/MyCountDownLatch.java b/src/main/java/ru/lionarius/sync/MyCountDownLatch.java
new file mode 100644
index 0000000..e8bc71a
--- /dev/null
+++ b/src/main/java/ru/lionarius/sync/MyCountDownLatch.java
@@ -0,0 +1,41 @@
+package ru.lionarius.sync;
+
+public class MyCountDownLatch {
+
+    private final Object lock = new Object();
+    private int count;
+
+    public MyCountDownLatch(int count) {
+        if (count < 0)
+            throw new IllegalArgumentException("Count cannot be negative");
+
+        this.count = count;
+    }
+
+    public void countDown() {
+        synchronized (lock) {
+            if (count <= 0)
+                return;
+
+            count--;
+
+            if (count == 0) {
+                lock.notifyAll();
+            }
+        }
+    }
+
+    public void await() throws InterruptedException {
+        synchronized (lock) {
+            while (count > 0) {
+                lock.wait();
+            }
+        }
+    }
+
+    public int getCount() {
+        synchronized (lock) {
+            return count;
+        }
+    }
+}
diff --git a/src/main/java/ru/lionarius/sync/MyReentrantLock.java b/src/main/java/ru/lionarius/sync/MyReentrantLock.java
new file mode 100644
index 0000000..513cd47
--- /dev/null
+++ b/src/main/java/ru/lionarius/sync/MyReentrantLock.java
@@ -0,0 +1,55 @@
+package ru.lionarius.sync;
+
+public class MyReentrantLock {
+    
+    private final Object lock = new Object();
+    
+    private int counter = 0;
+    private Thread owner;
+
+    public void lock() throws InterruptedException {
+        synchronized (lock) {
+            Thread current = Thread.currentThread();
+            
+            while (isLocked() && current != owner) {
+                lock.wait();
+            }
+            
+            counter++;
+            owner = current;
+        }
+    }
+    
+    public boolean tryLock() {
+        synchronized (lock) {
+            Thread current = Thread.currentThread();
+            
+            if (isLocked() && current != owner) {
+                return false;
+            }
+            
+            counter++;
+            owner = current;
+            return true;
+        }
+    }
+    
+    public void unlock() {
+        synchronized (lock) {
+            if (Thread.currentThread() != owner) {
+                throw new IllegalMonitorStateException("Not owner");
+            }
+            
+            counter--;
+            
+            if (counter == 0) {
+                owner = null;
+                lock.notify();
+            }
+        }
+    }
+    
+    private boolean isLocked() {
+        return counter > 0;
+    }
+}
diff --git a/src/main/java/ru/lionarius/sync/MySemaphore.java b/src/main/java/ru/lionarius/sync/MySemaphore.java
new file mode 100644
index 0000000..1eac0ed
--- /dev/null
+++ b/src/main/java/ru/lionarius/sync/MySemaphore.java
@@ -0,0 +1,45 @@
+package ru.lionarius.sync;
+
+public class MySemaphore {
+
+    private final Object lock = new Object();
+    private int permits;
+
+    public MySemaphore(int permits) {
+        this.permits = permits;
+    }
+
+    public void acquire() throws InterruptedException {
+        synchronized (lock) {
+            while (permits <= 0) {
+                lock.wait();
+            }
+
+            permits--;
+        }
+    }
+
+    public boolean tryAcquire() {
+        synchronized (lock) {
+            if (permits <= 0) {
+                return false;
+            }
+
+            permits--;
+            return true;
+        }
+    }
+
+    public void release() {
+        synchronized (lock) {
+            permits++;
+            lock.notify();
+        }
+    }
+
+    public int availablePermits() {
+        synchronized (lock) {
+            return permits;
+        }
+    }
+}
diff --git a/src/test/java/MyCountDownLatchTest.java b/src/test/java/MyCountDownLatchTest.java
new file mode 100644
index 0000000..6694999
--- /dev/null
+++ b/src/test/java/MyCountDownLatchTest.java
@@ -0,0 +1,112 @@
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.Timeout;
+import ru.lionarius.sync.MyCountDownLatch;
+
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class MyCountDownLatchTest {
+    @Test
+    void testInitialization() {
+        assertThrows(IllegalArgumentException.class, () -> new MyCountDownLatch(-1));
+        assertDoesNotThrow(() -> new MyCountDownLatch(0));
+        var latch = new MyCountDownLatch(5);
+        assertEquals(5, latch.getCount());
+    }
+
+    @Test
+    void testCountDown() {
+        var latch = new MyCountDownLatch(3);
+        assertEquals(3, latch.getCount());
+        latch.countDown();
+        assertEquals(2, latch.getCount());
+        latch.countDown();
+        assertEquals(1, latch.getCount());
+        latch.countDown();
+        assertEquals(0, latch.getCount());
+        latch.countDown();
+        assertEquals(0, latch.getCount());
+    }
+
+    @Test
+    void testAwait() throws InterruptedException {
+        var latch = new MyCountDownLatch(2);
+        var threadFinished = new AtomicBoolean(false);
+
+        var thread = new Thread(() -> {
+            try {
+                latch.await();
+                threadFinished.set(true);
+            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt();
+            }
+        });
+
+        thread.start();
+        Thread.sleep(100);
+        assertFalse(threadFinished.get());
+
+        latch.countDown();
+        Thread.sleep(100);
+        assertFalse(threadFinished.get());
+
+        latch.countDown();
+        thread.join(1000);
+        assertTrue(threadFinished.get());
+    }
+
+    @Test
+    void testMultipleThreads() throws InterruptedException {
+        final int THREAD_COUNT = 5;
+        var startLatch = new MyCountDownLatch(1);
+        var endLatch = new MyCountDownLatch(THREAD_COUNT);
+        AtomicBoolean[] threadsStarted = new AtomicBoolean[THREAD_COUNT];
+        AtomicBoolean[] threadsFinished = new AtomicBoolean[THREAD_COUNT];
+
+        for (int i = 0; i < THREAD_COUNT; i++) {
+            threadsStarted[i] = new AtomicBoolean(false);
+            threadsFinished[i] = new AtomicBoolean(false);
+            final int index = i;
+            new Thread(() -> {
+                try {
+                    startLatch.await();
+                    threadsStarted[index].set(true);
+                    Thread.sleep(100);
+                    threadsFinished[index].set(true);
+                    endLatch.countDown();
+                } catch (InterruptedException e) {
+                    Thread.currentThread().interrupt();
+                }
+            }).start();
+        }
+
+        Thread.sleep(100);
+        for (var started : threadsStarted) {
+            assertFalse(started.get());
+        }
+
+        startLatch.countDown();
+        Thread.sleep(50);
+
+        for (var started : threadsStarted) {
+            assertTrue(started.get());
+        }
+
+        endLatch.await();
+        for (var finished : threadsFinished) {
+            assertTrue(finished.get());
+        }
+        assertEquals(0, endLatch.getCount());
+    }
+
+    @Test
+    @Timeout(value = 1000, unit = TimeUnit.MILLISECONDS)
+    void testZeroCount() throws InterruptedException {
+        var latch = new MyCountDownLatch(0);
+        assertEquals(0, latch.getCount());
+        latch.await();
+        assertTrue(true);
+    }
+}
diff --git a/src/test/java/MyReentrantLockTest.java b/src/test/java/MyReentrantLockTest.java
new file mode 100644
index 0000000..d0356d8
--- /dev/null
+++ b/src/test/java/MyReentrantLockTest.java
@@ -0,0 +1,89 @@
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.Timeout;
+import ru.lionarius.sync.MyReentrantLock;
+
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class MyReentrantLockTest {
+    private MyReentrantLock lock;
+
+    @BeforeEach
+    void setUp() {
+        lock = new MyReentrantLock();
+    }
+
+    @Test
+    @Timeout(value = 1000, unit = TimeUnit.MILLISECONDS)
+    void testLockAndUnlock() throws InterruptedException {
+        lock.lock();
+        assertTrue(lock.tryLock());
+        lock.unlock();
+        lock.unlock();
+    }
+
+    @Test
+    @Timeout(value = 1000, unit = TimeUnit.MILLISECONDS)
+    void testTryLock() throws InterruptedException {
+        assertTrue(lock.tryLock());
+
+        var otherThreadLocked = new AtomicBoolean(false);
+        var otherThread = new Thread(() -> {
+            otherThreadLocked.set(lock.tryLock());
+        });
+        otherThread.start();
+        otherThread.join();
+
+        assertFalse(otherThreadLocked.get()); // Другой поток не должен получить блокировку
+        lock.unlock();
+    }
+
+    @Test
+    @Timeout(value = 1000, unit = TimeUnit.MILLISECONDS)
+    void testUnlockByDifferentThread() throws InterruptedException {
+        lock.lock();
+
+        var otherThread = new Thread(() -> {
+            assertThrows(IllegalMonitorStateException.class, lock::unlock);
+        });
+        otherThread.start();
+        otherThread.join();
+
+        lock.unlock();
+    }
+
+    @Test
+    @Timeout(value = 1000, unit = TimeUnit.MILLISECONDS)
+    void testMultipleThreads() throws InterruptedException {
+        int threadCount = 10;
+        Thread[] threads = new Thread[threadCount];
+        AtomicBoolean[] threadsCompleted = new AtomicBoolean[threadCount];
+
+        for (int i = 0; i < threadCount; i++) {
+            final int index = i;
+            threadsCompleted[i] = new AtomicBoolean(false);
+            threads[i] = new Thread(() -> {
+                try {
+                    lock.lock();
+                    Thread.sleep(10);
+                    lock.unlock();
+                    threadsCompleted[index].set(true);
+                } catch (InterruptedException e) {
+                    Thread.currentThread().interrupt();
+                }
+            });
+            threads[i].start();
+        }
+
+        for (var thread : threads) {
+            thread.join();
+        }
+
+        for (var completed : threadsCompleted) {
+            assertTrue(completed.get(), "Все потоки должны завершить свою работу");
+        }
+    }
+}
diff --git a/src/test/java/MySemaphoreTest.java b/src/test/java/MySemaphoreTest.java
new file mode 100644
index 0000000..0eb4efe
--- /dev/null
+++ b/src/test/java/MySemaphoreTest.java
@@ -0,0 +1,112 @@
+import org.junit.jupiter.api.Test;
+import ru.lionarius.sync.MySemaphore;
+
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class MySemaphoreTest {
+    @Test
+    void testInitialization() {
+        assertDoesNotThrow(() -> new MySemaphore(-1));
+        assertDoesNotThrow(() -> new MySemaphore(0));
+        var semaphore = new MySemaphore(5);
+        assertEquals(5, semaphore.availablePermits());
+    }
+
+    @Test
+    void testAcquireAndRelease() throws InterruptedException {
+        var semaphore = new MySemaphore(2);
+        assertEquals(2, semaphore.availablePermits());
+        semaphore.acquire();
+        assertEquals(1, semaphore.availablePermits());
+        semaphore.acquire();
+        assertEquals(0, semaphore.availablePermits());
+        assertFalse(semaphore.tryAcquire());
+        semaphore.release();
+        assertEquals(1, semaphore.availablePermits());
+        assertTrue(semaphore.tryAcquire());
+        assertEquals(0, semaphore.availablePermits());
+    }
+
+    @Test
+    void testTryAcquire() {
+        var semaphore = new MySemaphore(2);
+        assertTrue(semaphore.tryAcquire());
+        assertEquals(1, semaphore.availablePermits());
+        assertTrue(semaphore.tryAcquire());
+        assertEquals(0, semaphore.availablePermits());
+        assertFalse(semaphore.tryAcquire());
+        assertEquals(0, semaphore.availablePermits());
+    }
+
+    @Test
+    void testMultipleThreads() throws InterruptedException {
+        final int THREAD_COUNT = 10;
+        final int PERMITS = 3;
+        var semaphore = new MySemaphore(PERMITS);
+        var startLatch = new CountDownLatch(1);
+        var finishLatch = new CountDownLatch(THREAD_COUNT);
+        var concurrentThreads = new AtomicInteger(0);
+        var maxConcurrentThreads = new AtomicInteger(0);
+
+        for (int i = 0; i < THREAD_COUNT; i++) {
+            new Thread(() -> {
+                try {
+                    startLatch.await();
+                    semaphore.acquire();
+                    int current = concurrentThreads.incrementAndGet();
+                    maxConcurrentThreads.updateAndGet(max -> Math.max(max, current));
+                    Thread.sleep(100); // Имитация работы
+                    concurrentThreads.decrementAndGet();
+                    semaphore.release();
+                    finishLatch.countDown();
+                } catch (InterruptedException e) {
+                    Thread.currentThread().interrupt();
+                }
+            }).start();
+        }
+
+        startLatch.countDown();
+        assertTrue(finishLatch.await(5, TimeUnit.SECONDS));
+        assertEquals(PERMITS, maxConcurrentThreads.get());
+        assertEquals(PERMITS, semaphore.availablePermits());
+    }
+
+    @Test
+    void testBlockingAcquire() throws InterruptedException {
+        var semaphore = new MySemaphore(1);
+        semaphore.acquire();
+        assertEquals(0, semaphore.availablePermits());
+
+        var thread = new Thread(() -> {
+            try {
+                semaphore.acquire();
+            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt();
+            }
+        });
+
+        thread.start();
+        Thread.sleep(100); // Даем время потоку начать ожидание
+        assertTrue(thread.isAlive());
+        assertEquals(0, semaphore.availablePermits());
+
+        semaphore.release();
+        thread.join(1000);
+        assertFalse(thread.isAlive());
+        assertEquals(0, semaphore.availablePermits());
+    }
+
+    @Test
+    void testAvailablePermits() {
+        var semaphore = new MySemaphore(5);
+        assertEquals(5, semaphore.availablePermits());
+        semaphore.tryAcquire();
+        assertEquals(4, semaphore.availablePermits());
+        semaphore.release();
+        assertEquals(5, semaphore.availablePermits());
+    }
+}