[BAEL-4500] Add locked ownable synchronizers example code (#12608)

* Add locked ownable synchronizers example code

* refactor application snippet

core-java-modules/core-java-concurrency-advanced-4/src/main/java/com/baeldung/ownablesynchronizers/Application.java

@@ -0,0 +1,45 @@
+package com.baeldung.ownablesynchronizers;
+
+import java.util.concurrent.locks.ReentrantLock;
+
+public class Application {
+
+    public static Thread createThread(ReentrantLock mainLock, ReentrantLock otherLock, String threadName) {
+        return new Thread(() -> {
+            try {
+                mainLock.lock();
+
+                // synchronized block here allows us to wait for other thread to lock,
+                // in order to simulate a deadlock
+                synchronized (Application.class) {
+                    Application.class.notify();
+                    if (!otherLock.isLocked()) {
+                        Application.class.wait();
+                    }
+                }
+
+                // thread will hang here
+                otherLock.lock();
+
+                System.out.println(threadName + ": Finished");
+                mainLock.unlock();
+                otherLock.unlock();
+            } catch (InterruptedException e) {
+                System.out.println(threadName + ": " + e.getMessage());
+            }
+        });
+    }
+
+    public static void main(String[] args) throws Exception {
+        ReentrantLock firstLock = new ReentrantLock(true);
+        ReentrantLock secondLock = new ReentrantLock(true);
+        Thread first = createThread(firstLock, secondLock, "Thread-0");
+        Thread second = createThread(secondLock, firstLock, "Thread-1");
+
+        first.start();
+        second.start();
+
+        first.join();
+        second.join();
+    }
+}