#970 single logging framework should be enforced (#982)

* #496 Add pipeline module to parent pom ✨

* #496: Add main application class and test for pipeline

* #496: Checkstyle format and add log messages on pipeline stages 🎨

* #496: Fill readme sections of pipeline ✨

* #496: Javadocs and checkstyle formatting 🎨

* #496: Follow PMD checks and add more explanation as block comment on App.java

* #496: Apply requested PR changes by iluwatar 🎨

* #970: Replace log4j usage on commander pattern to Slf4j API 🎨

* #970: Replace log4j usage on dao pattern to Slf4j API 🎨

* #970: Replace log4j usage on data mapper pattern to Slf4j API 🎨

* #970: Remove log4j dependency on data transfer object pom 🔥

* #970: Replace log4j usage on module pattern to Slf4j API 🎨

* #970: Replace log4j usage on serverless pattern to Slf4j API 🎨

This also removes the aws log4j dependency

* #970: Remove unnecessary gitignore line for log4j.xml 🔥

* #970: Remove remaining remnants of log4j 🔥

* #970: Replace System.out logging with appropriate logging methods 🎨

* #970: Replace System.out method references to Logger::info 🎨

master-worker-pattern/src/main/java/com/iluwatar/masterworker/App.java

@@ -23,6 +23,8 @@
 package com.iluwatar.masterworker;
 
 import com.iluwatar.masterworker.system.ArrayTransposeMasterWorker;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * <p>The <b><em>Master-Worker</em></b> pattern is used when the problem at hand can be solved by dividing into 
@@ -45,7 +47,8 @@ import com.iluwatar.masterworker.system.ArrayTransposeMasterWorker;
  */
 
 public class App {
-  
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(App.class);
   /**
    * Program entry point.
    * @param args command line args
@@ -60,10 +63,9 @@ public class App {
     ArrayResult result = (ArrayResult) mw.getResult(input);    
     if (result != null) {
       ArrayUtilityMethods.printMatrix(inputMatrix);
-      System.out.println("");
       ArrayUtilityMethods.printMatrix(result.data);
     } else {
-      System.out.println("Please enter non-zero input");
+      LOGGER.info("Please enter non-zero input");
     }
   }
 

master-worker-pattern/src/main/java/com/iluwatar/masterworker/ArrayUtilityMethods.java

@@ -22,6 +22,9 @@
  */
 package com.iluwatar.masterworker;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import java.util.Random;
 
 /**
@@ -29,7 +32,8 @@ import java.util.Random;
  */
 
 public class ArrayUtilityMethods {
- 
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(ArrayUtilityMethods.class);
   /**
    * Method arraysSame compares 2 arrays @param a1 and @param a2
    * and @return whether their values are equal (boolean).
@@ -100,9 +104,9 @@ public class ArrayUtilityMethods {
     //prints out int[][]
     for (int i = 0; i < matrix.length; i++) {
       for (int j = 0; j < matrix[0].length; j++) {
-        System.out.print(matrix[i][j] + " ");
+        LOGGER.info(matrix[i][j] + " ");
       }
-      System.out.println("");
+      LOGGER.info("");
     }
   }