diff --git a/src/main/java/Operations/CheckAnomaly.java b/src/main/java/Operations/CheckAnomaly.java
index 62be2b7dd6..475bb9f6c6 100644
--- a/src/main/java/Operations/CheckAnomaly.java
+++ b/src/main/java/Operations/CheckAnomaly.java
@@ -42,11 +42,11 @@ public static Boolean checkDuplicateOverdue(Task task) {
         String assignee = task.getAssignee();
         String date = task.getDate().toString();
         ArrayList<Task> temp = OverdueList.getOverdueList();
-        for (int i = 0; i < temp.size(); i++) {
-            if (temp.get(i).getDescription().equals(name)
-                    && temp.get(i).getAssignee().equals(assignee)
-                    && temp.get(i).getDate().toString().equals(date)
-                    && temp.get(i).getClass().equals(task.getClass())) {
+        for (Task value : temp) {
+            if (value.getDescription().equals(name)
+                    && value.getAssignee().equals(assignee)
+                    && value.getDate().toString().equals(date)
+                    && value.getClass().equals(task.getClass())) {
                 return true;
             }
         }
diff --git a/src/main/java/Operations/OverdueList.java b/src/main/java/Operations/OverdueList.java
index e98de7431b..f62d24e2bb 100644
--- a/src/main/java/Operations/OverdueList.java
+++ b/src/main/java/Operations/OverdueList.java
@@ -38,25 +38,25 @@ public void add(Task task) {
     public void reschedule(int[] idx, TaskList taskList) throws RoomShareException {
         int[] index = idx.clone();
         if (index.length ==1) {
-            if (index[0] < 0 || index[0] >= Overdue.size()) {
+            if (index[0] < 0 || index[0] >= overdue.size()) {
                 System.out.println("This are your tasks in your Overdue list");
                 list();
                 throw new RoomShareException(ExceptionType.outOfBounds);
             } else {
-                taskList.add(Overdue.get(index[0]));
-                Overdue.get(index[0]).setOverdue(false);
+                taskList.add(overdue.get(index[0]));
+                overdue.get(index[0]).setOverdue(false);
             }
         } else {
-            if (index[0] < 0 || index[0] >= Overdue.size() || index[1] < 0 || index[1] >= Overdue.size()) {
+            if (index[0] < 0 || index[0] >= overdue.size() || index[1] < 0 || index[1] >= overdue.size()) {
                 throw new RoomShareException(ExceptionType.outOfBounds);
             }
             for (int i = index[0]; i <= index[1]; i++){
-                taskList.add(Overdue.get(i));
-                Overdue.get(i).setOverdue(false);
+                taskList.add(overdue.get(i));
+                overdue.get(i).setOverdue(false);
             }
         }
         for (int i = 0; i < index.length; i++){
-            Overdue.removeIf(n -> !n.getOverdue());
+            overdue.removeIf(n -> !n.getOverdue());
         }
     }
 
diff --git a/src/main/java/Operations/TaskList.java b/src/main/java/Operations/TaskList.java
index 56d29abde3..19d77cf4fd 100644
--- a/src/main/java/Operations/TaskList.java
+++ b/src/main/java/Operations/TaskList.java
@@ -80,7 +80,7 @@ public void list(OverdueList overdueList) throws RoomShareException {
             for (int i = 0; i < tasks.size(); i++) {
                 if (new Date().after(tasks.get(i).getDate()) && !(tasks.get(i) instanceof Leave)) {
                     tasks.get(i).setOverdue(true);
-                    if (CheckAnomaly.checkDuplicateOverdue(tasks.get(i))) {
+                    if (!CheckAnomaly.checkDuplicateOverdue(tasks.get(i))) {
                         // no duplicates in overdue list
                         overdueList.add(tasks.get(i));
                     }
diff --git a/src/main/java/RoomShare.java b/src/main/java/RoomShare.java
index 529645bc4d..4eb819bf00 100644
--- a/src/main/java/RoomShare.java
+++ b/src/main/java/RoomShare.java
@@ -22,7 +22,6 @@ public class RoomShare {
     private TaskList taskList;
     private OverdueList overdueList;
     private Parser parser;
-    private RecurHandler recurHandler;
     private TempDeleteList tempDeleteList;
     private TaskCreator taskCreator;
     private Help help;
@@ -32,7 +31,7 @@ public class RoomShare {
      * Constructor of a RoomShare class. Creates all necessary objects and collections for RoomShare to run
      * Also loads the ArrayList of tasks from the data.txt file
      */
-    public RoomShare() throws RoomShareException {
+    private RoomShare() throws RoomShareException {
         ui = new Ui();
         help = new Help();
         ui.startUp();
@@ -57,7 +56,7 @@ public RoomShare() throws RoomShareException {
             overdueList = new OverdueList(emptyList);
         }
         listRoutine = new ListRoutine(taskList, overdueList);
-        recurHandler = new RecurHandler(taskList);
+        RecurHandler recurHandler = new RecurHandler(taskList);
         if (recurHandler.checkRecurrence()) {
             ui.showChangeInTaskList();
             taskList.list(overdueList);
@@ -68,7 +67,7 @@ public RoomShare() throws RoomShareException {
     /**
      * Deals with the operation flow of RoomShare.
      */
-    public void run() throws RoomShareException, IOException, InterruptedException {
+    private void run() throws RoomShareException, IOException, InterruptedException {
         boolean isExit = false;
         while (!isExit) {
             TaskType type;
@@ -408,7 +407,6 @@ public void run() throws RoomShareException, IOException, InterruptedException {
                         } catch (RoomShareException e) {
                             ui.showError(e);
                         }
-                        listRoutine.list();
                     } else {
                         ui.showTagged(input);
                         int[] doneArray = taskList.listTagged(input);