Code cleanup (#1461)

* Code cleanup

* Fix flux tests

* Fix checkstyle errors

* Fix compile error

visitor/README.md

@@ -32,7 +32,7 @@ Given the army unit example from above, we first have the Unit and UnitVisitor b
 ```java
 public abstract class Unit {
 
-  private Unit[] children;
+  private final Unit[] children;
 
   public Unit(Unit... children) {
     this.children = children;

visitor/src/main/java/com/iluwatar/visitor/Unit.java

@@ -1,45 +1,45 @@
-/*
- * The MIT License
- * Copyright © 2014-2019 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
-package com.iluwatar.visitor;
-
-import java.util.Arrays;
-
-/**
- * Interface for the nodes in hierarchy.
- */
-public abstract class Unit {
-
-  private Unit[] children;
-
-  public Unit(Unit... children) {
-    this.children = children;
-  }
-
-  /**
-   * Accept visitor.
-   */
-  public void accept(UnitVisitor visitor) {
-    Arrays.stream(children).forEach(child -> child.accept(visitor));
-  }
-}
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.visitor;
+
+import java.util.Arrays;
+
+/**
+ * Interface for the nodes in hierarchy.
+ */
+public abstract class Unit {
+
+  private final Unit[] children;
+
+  public Unit(Unit... children) {
+    this.children = children;
+  }
+
+  /**
+   * Accept visitor.
+   */
+  public void accept(UnitVisitor visitor) {
+    Arrays.stream(children).forEach(child -> child.accept(visitor));
+  }
+}

visitor/src/test/java/com/iluwatar/visitor/VisitorTest.java

@@ -123,7 +123,7 @@ public abstract class VisitorTest<V extends UnitVisitor> {
   }
 
   private class InMemoryAppender extends AppenderBase<ILoggingEvent> {
-    private List<ILoggingEvent> log = new LinkedList<>();
+    private final List<ILoggingEvent> log = new LinkedList<>();
 
     public InMemoryAppender() {
       ((Logger) LoggerFactory.getLogger("root")).addAppender(this);