Java 11 migrate remaining p (#1122)

* Moves partial-response to Java 11

* Moves pipeline to Java 11

* Moves poison-pill to Java 11

* Moves priority-queue to Java 11

* Moves private-class-data to Java 11

* Moves producer-consumer to Java 11

* Moves promise to Java 11

* Moves property to Java 11

* Moves prototype to Java 11

* Moves proxy to Java 11

* Corrects checkstyle errors

* Fixes build for pipeline pattern

pipeline/src/test/java/com/iluwatar/pipeline/AppTest.java

@@ -32,7 +32,6 @@ public class AppTest {
 
   @Test
   public void test() {
-    String[] args = {};
-    App.main(args);
+    App.main(new String[]{});
   }
 }

pipeline/src/test/java/com/iluwatar/pipeline/PipelineTest.java

@@ -23,10 +23,10 @@
 
 package com.iluwatar.pipeline;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 
+import org.junit.jupiter.api.Test;
+
 /**
  * Test for {@link Pipeline}
  */
@@ -34,12 +34,12 @@ public class PipelineTest {
 
   @Test
   public void testAddHandlersToPipeline() {
-    Pipeline<String, char[]> filters = new Pipeline<>(new RemoveAlphabetsHandler())
+    var filters = new Pipeline<>(new RemoveAlphabetsHandler())
         .addHandler(new RemoveDigitsHandler())
         .addHandler(new ConvertToCharArrayHandler());
 
     assertArrayEquals(
-        new char[] {'#', '!', '(', '&', '%', '#', '!'},
+        new char[]{'#', '!', '(', '&', '%', '#', '!'},
         filters.execute("#H!E(L&L0O%THE3R#34E!")
     );
   }