Spark graphx moved to a new project due to a incompatibility of scala compiler

libraries/src/main/java/com/baeldung/jdeffered/ThreadSafeDemo.java

@@ -0,0 +1,36 @@
+package com.baeldung.jdeffered;
+
+import org.jdeferred.Deferred;
+import org.jdeferred.DeferredManager;
+import org.jdeferred.Promise;
+import org.jdeferred.impl.DefaultDeferredManager;
+import org.jdeferred.impl.DeferredObject;
+
+public class ThreadSafeDemo {
+
+    public static void task() {
+        DeferredManager dm = new DefaultDeferredManager();
+        Deferred<String, String, String> deferred = new DeferredObject<>();
+        Promise<String, String, String> p1 = deferred.promise();
+        Promise<String, String, String> p = dm.when(p1).done(r -> System.out.println("done")).fail(r -> System.out.println("fail"));
+
+        synchronized (p) {
+            while (p.isPending()) {
+                try {
+                    p.wait();
+                } catch (InterruptedException e) {
+                    e.printStackTrace();
+                }
+            }
+        }
+
+        try {
+            p.waitSafely();
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+
+        deferred.resolve("Hello Baeldung");
+    }
+
+}