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

private-class-data/src/main/java/com/iluwatar/privateclassdata/App.java

@@ -46,13 +46,13 @@ public class App {
    */
   public static void main(String[] args) {
     // stew is mutable
-    Stew stew = new Stew(1, 2, 3, 4);
+    var stew = new Stew(1, 2, 3, 4);
     stew.mix();
     stew.taste();
     stew.mix();
 
     // immutable stew protected with Private Class Data pattern
-    ImmutableStew immutableStew = new ImmutableStew(2, 4, 3, 6);
+    var immutableStew = new ImmutableStew(2, 4, 3, 6);
     immutableStew.mix();
   }
 }

private-class-data/src/test/java/com/iluwatar/privateclassdata/AppTest.java

@@ -26,15 +26,12 @@ package com.iluwatar.privateclassdata;
 import org.junit.jupiter.api.Test;
 
 /**
- * 
  * Application test
- *
  */
 public class AppTest {
 
   @Test
   public void test() {
-    String[] args = {};
-    App.main(args);
+    App.main(new String[]{});
   }
 }

private-class-data/src/test/java/com/iluwatar/privateclassdata/ImmutableStewTest.java

@@ -23,13 +23,13 @@
 
 package com.iluwatar.privateclassdata;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
 import com.iluwatar.privateclassdata.utils.InMemoryAppender;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
 /**
  * Date: 12/27/15 - 10:46 PM
  *
@@ -54,10 +54,10 @@ public class ImmutableStewTest {
    */
   @Test
   public void testMix() {
-    final Stew stew = new Stew(1, 2, 3, 4);
-    final String expectedMessage = "Mixing the stew we find: 1 potatoes, 2 carrots, 3 meat and 4 peppers";
+    var stew = new Stew(1, 2, 3, 4);
+    var expectedMessage = "Mixing the stew we find: 1 potatoes, 2 carrots, 3 meat and 4 peppers";
 
-    for (int i = 0; i < 20; i++) {
+    for (var i = 0; i < 20; i++) {
       stew.mix();
       assertEquals(expectedMessage, appender.getLastMessage());
     }
@@ -70,15 +70,17 @@ public class ImmutableStewTest {
    */
   @Test
   public void testDrink() {
-    final Stew stew = new Stew(1, 2, 3, 4);
+    final var stew = new Stew(1, 2, 3, 4);
     stew.mix();
 
-    assertEquals("Mixing the stew we find: 1 potatoes, 2 carrots, 3 meat and 4 peppers",  appender.getLastMessage());
+    assertEquals("Mixing the stew we find: 1 potatoes, 2 carrots, 3 meat and 4 peppers", appender
+        .getLastMessage());
 
     stew.taste();
-    assertEquals("Tasting the stew",  appender.getLastMessage());
+    assertEquals("Tasting the stew", appender.getLastMessage());
 
     stew.mix();
-    assertEquals("Mixing the stew we find: 0 potatoes, 1 carrots, 2 meat and 3 peppers",  appender.getLastMessage());
+    assertEquals("Mixing the stew we find: 0 potatoes, 1 carrots, 2 meat and 3 peppers", appender
+        .getLastMessage());
   }
 }

private-class-data/src/test/java/com/iluwatar/privateclassdata/StewTest.java

@@ -23,13 +23,13 @@
 
 package com.iluwatar.privateclassdata;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
 import com.iluwatar.privateclassdata.utils.InMemoryAppender;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
 /**
  * Date: 12/27/15 - 10:46 PM
  *
@@ -54,11 +54,11 @@ public class StewTest {
    */
   @Test
   public void testMix() {
-    final ImmutableStew stew = new ImmutableStew(1, 2, 3, 4);
-    final String expectedMessage = "Mixing the immutable stew we find: 1 potatoes, "
+    final var stew = new ImmutableStew(1, 2, 3, 4);
+    final var expectedMessage = "Mixing the immutable stew we find: 1 potatoes, "
         + "2 carrots, 3 meat and 4 peppers";
 
-    for (int i = 0; i < 20; i++) {
+    for (var i = 0; i < 20; i++) {
       stew.mix();
       assertEquals(expectedMessage, appender.getLastMessage());
     }

private-class-data/src/test/java/com/iluwatar/privateclassdata/utils/InMemoryAppender.java

@@ -26,10 +26,9 @@ package com.iluwatar.privateclassdata.utils;
 import ch.qos.logback.classic.Logger;
 import ch.qos.logback.classic.spi.ILoggingEvent;
 import ch.qos.logback.core.AppenderBase;
-import org.slf4j.LoggerFactory;
-
 import java.util.LinkedList;
 import java.util.List;
+import org.slf4j.LoggerFactory;
 
 /**
  * InMemory Log Appender Util.