diff --git a/src/main/java/it/tdlight/common/ConstructorDetector.java b/src/main/java/it/tdlight/common/ConstructorDetector.java
index ca0904e..03d4c73 100644
--- a/src/main/java/it/tdlight/common/ConstructorDetector.java
+++ b/src/main/java/it/tdlight/common/ConstructorDetector.java
@@ -28,7 +28,10 @@ import java.util.concurrent.ConcurrentHashMap;
 @SuppressWarnings("rawtypes")
 public final class ConstructorDetector {
 
-	static {
+	private static ConcurrentHashMap<Integer, Class> constructorHashMap;
+	private static ConcurrentHashMap<Class, Integer> constructorHashMapInverse;
+
+	private static void tryInit() {
 		// Call this to load static methods and prevent errors during startup!
 		try {
 			Init.start();
@@ -37,13 +40,10 @@ public final class ConstructorDetector {
 		}
 	}
 
-	private static ConcurrentHashMap<Integer, Class> constructorHashMap;
-	private static ConcurrentHashMap<Class, Integer> constructorHashMapInverse;
-
 	/**
 	 * Initialize the ConstructorDetector, it is called from the Init class.
 	 */
-	public static void init() {
+	static void init() {
 		if (constructorHashMap != null) {
 			return;
 		}
@@ -59,6 +59,7 @@ public final class ConstructorDetector {
 	 * @return The class related to CONSTRUCTOR.
 	 */
 	public static Class getClass(int CONSTRUCTOR) {
+		tryInit();
 		return constructorHashMap.getOrDefault(CONSTRUCTOR, null);
 	}
 
@@ -69,6 +70,7 @@ public final class ConstructorDetector {
 	 * @return The CONSTRUCTOR.
 	 */
 	public static int getConstructor(Class<? extends TdApi.Object> clazz) {
+		tryInit();
 		return Objects.requireNonNull(constructorHashMapInverse.get(clazz));
 	}
 
diff --git a/src/main/java/it/tdlight/common/Init.java b/src/main/java/it/tdlight/common/Init.java
index 018e97a..4e6b4fc 100644
--- a/src/main/java/it/tdlight/common/Init.java
+++ b/src/main/java/it/tdlight/common/Init.java
@@ -32,23 +32,27 @@ public final class Init {
 
 	public static final Logger LOG = LoggerFactory.getLogger(Init.class);
 
-	private static boolean started = false;
+	private static volatile boolean started = false;
 
 	/**
 	 * Initialize Tdlib
 	 *
 	 * @throws CantLoadLibrary An exception that is thrown when the LoadLibrary class fails to load the library.
 	 */
-	public synchronized static void start() throws CantLoadLibrary {
+	public static void start() throws CantLoadLibrary {
 		if (!started) {
-			LoadLibrary.load("tdjni");
-			ConstructorDetector.init();
-			try {
-				NativeClientAccess.execute(new SetLogVerbosityLevel(1));
-			} catch (Throwable ex) {
-				LOG.error("Can't set verbosity level on startup", ex);
+			synchronized (Init.class) {
+				if (!started) {
+					LoadLibrary.load("tdjni");
+					ConstructorDetector.init();
+					try {
+						NativeClientAccess.execute(new SetLogVerbosityLevel(1));
+					} catch (Throwable ex) {
+						LOG.error("Can't set verbosity level on startup", ex);
+					}
+					started = true;
+				}
 			}
-			started = true;
 		}
 	}
 }
diff --git a/src/main/java/it/tdlight/common/internal/InternalClientManager.java b/src/main/java/it/tdlight/common/internal/InternalClientManager.java
index 056cc2c..3182722 100644
--- a/src/main/java/it/tdlight/common/internal/InternalClientManager.java
+++ b/src/main/java/it/tdlight/common/internal/InternalClientManager.java
@@ -28,12 +28,6 @@ public final class InternalClientManager implements AutoCloseable {
 	private final AtomicLong currentQueryId = new AtomicLong();
 
 	private InternalClientManager(String implementationName) {
-		try {
-			Init.start();
-		} catch (Throwable ex) {
-			ex.printStackTrace();
-			System.exit(1);
-		}
 		this.implementationName = implementationName;
 		responseReceiver = new NativeResponseReceiver(this::handleClientEvents);
 	}
@@ -46,6 +40,12 @@ public final class InternalClientManager implements AutoCloseable {
 			return false;
 		}
 		if (startCalled.compareAndSet(false, true)) {
+			try {
+				Init.start();
+			} catch (Throwable ex) {
+				ex.printStackTrace();
+				System.exit(1);
+			}
 			responseReceiver.start();
 			return true;
 		} else {
@@ -54,14 +54,12 @@ public final class InternalClientManager implements AutoCloseable {
 	}
 
 	public static InternalClientManager get(String implementationName) {
-		InternalClientManager clientManager = INSTANCE.updateAndGet(val -> {
+		return INSTANCE.updateAndGet(val -> {
 			if (val == null) {
 				return new InternalClientManager(implementationName);
 			}
 			return val;
 		});
-		clientManager.startIfNeeded();
-		return clientManager;
 	}
 
 	private void handleClientEvents(int clientId,
@@ -125,6 +123,7 @@ public final class InternalClientManager implements AutoCloseable {
 	}
 
 	public void registerClient(int clientId, ClientEventsHandler internalClient) {
+		this.startIfNeeded();
 		boolean replaced = registeredClientEventHandlers.put(clientId, internalClient) != null;
 		if (replaced) {
 			throw new IllegalStateException("Client " + clientId + " already registered");
diff --git a/src/main/java/it/tdlight/common/internal/ResponseReceiver.java b/src/main/java/it/tdlight/common/internal/ResponseReceiver.java
index 22e2081..9445a82 100644
--- a/src/main/java/it/tdlight/common/internal/ResponseReceiver.java
+++ b/src/main/java/it/tdlight/common/internal/ResponseReceiver.java
@@ -277,6 +277,9 @@ abstract class ResponseReceiver extends Thread implements AutoCloseable {
 		if (startCalled.get()) {
 			if (closeCalled.compareAndSet(false, true)) {
 				this.closeWait.await();
+				if (registeredClients.isEmpty()) {
+					this.interrupt();
+				}
 			}
 		}
 	}