local variable type inference changes (#1042)

* local variable type inference changes

local variable type inference changes for thread pool design pattern

* local variable type inference changes

local variable type inference changes for ThreadPool design pattern

thread-pool/src/main/java/com/iluwatar/threadpool/App.java

@@ -81,13 +81,13 @@ public class App {
     // unbounded queue. At any point, at most nThreads threads will be active processing
     // tasks. If additional tasks are submitted when all threads are active, they will wait
     // in the queue until a thread is available.
-    ExecutorService executor = Executors.newFixedThreadPool(3);
+    var executor = Executors.newFixedThreadPool(3);
 
     // Allocate new worker for each task
     // The worker is executed when a thread becomes
     // available in the thread pool
     for (int i = 0; i < tasks.size(); i++) {
-      Runnable worker = new Worker(tasks.get(i));
+      var worker = new Worker(tasks.get(i));
       executor.execute(worker);
     }
     // All tasks were executed, now shutdown