diff --git a/src/main/java/me/alex4386/gachon/sw14462/Main.java b/src/main/java/me/alex4386/gachon/sw14462/Main.java
index db42bd0..4bd4993 100644
--- a/src/main/java/me/alex4386/gachon/sw14462/Main.java
+++ b/src/main/java/me/alex4386/gachon/sw14462/Main.java
@@ -5,7 +5,7 @@
 import java.util.*;
 
 public class Main {
-    public static String currentTarget = "day24";
+    public static String currentTarget = "day25";
     public static boolean fallbackToLatest = true;
 
     public static Map<String, Class<?>> getAvailableTargetClassNames() {
diff --git a/src/main/java/me/alex4386/gachon/sw14462/day25/Main.java b/src/main/java/me/alex4386/gachon/sw14462/day25/Main.java
new file mode 100644
index 0000000..65e6188
--- /dev/null
+++ b/src/main/java/me/alex4386/gachon/sw14462/day25/Main.java
@@ -0,0 +1,20 @@
+package me.alex4386.gachon.sw14462.day25;
+
+import me.alex4386.gachon.sw14462.utils.Chainloader;
+
+public class Main {
+    public static String chainloadTarget = "ex14_11";
+
+    public static void main(String[] args) throws Throwable {
+        String packageName = Main.class.getPackage().getName();
+        String chainLoadTargetClass = packageName + "." + chainloadTarget + ".Main";
+
+        try {
+            Chainloader.chainloadTarget(chainLoadTargetClass, args);
+        } catch (Exception e) {
+            throw e;
+        }
+    }
+
+}
+
diff --git a/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_1/Main.java b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_1/Main.java
new file mode 100644
index 0000000..1223792
--- /dev/null
+++ b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_1/Main.java
@@ -0,0 +1,44 @@
+package me.alex4386.gachon.sw14462.day25.ex14_1;
+
+import java.util.ArrayList;
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+        ArrayList<Pet> pets = new ArrayList<>();
+
+        while (true) {
+            System.out.print("Enter the name of the pet (type \"exit\" to exit): ");
+            String name = scanner.nextLine();
+            if (name.equals("exit")) break;
+
+            System.out.print("Enter the age of the pet: ");
+            int age = scanner.nextInt();
+            scanner.nextLine();
+
+            System.out.print("Enter the weight of the pet: ");
+            double weight = scanner.nextDouble();
+
+            Pet pet = new Pet(name, age, weight);
+            pets.add(pet);
+
+            scanner.nextLine();
+        }
+
+        // sort by its name.
+        for (int i = 0; i < pets.size(); i++) {
+            for (int j = i + 1; j < pets.size(); j++) {
+                if (pets.get(i).getName().compareTo(pets.get(j).getName()) > 0) {
+                    Pet temp = pets.get(i);
+                    pets.set(i, pets.get(j));
+                    pets.set(j, temp);
+                }
+            }
+        }
+
+        for (Pet pet : pets) {
+            pet.writeOutput();
+        }
+    }
+}
diff --git a/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_1/Pet.java b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_1/Pet.java
new file mode 100644
index 0000000..1a0fbda
--- /dev/null
+++ b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_1/Pet.java
@@ -0,0 +1,117 @@
+package me.alex4386.gachon.sw14462.day25.ex14_1;
+
+/**
+ Class for basic pet data: name, age, and weight. */
+public class Pet {
+    private String name;
+    private int age; // in years
+    private double weight; // in pounds
+
+    public Pet() // Default constructor
+    {
+        name = "No name yet.";
+        age = 0;
+        weight = 0;
+    }
+
+    public Pet(String initialName, int initialAge,
+               double initialWeight) {
+        name = initialName;
+        if ((initialAge < 0) || (initialWeight < 0)) {
+            System.out.println("Error: Negative age or weight.");
+            System.exit(0);
+        } else {
+            age = initialAge;
+            weight = initialWeight;
+        }
+    }
+
+    public void setPet(String newName, int newAge,
+                       double newWeight) {
+        name = newName;
+        if ((newAge < 0) || (newWeight < 0)) {
+            System.out.println("Error: Negative age or weight.");
+            System.exit(0);
+        } else {
+            age = newAge;
+            weight = newWeight;
+        }
+    }
+
+    public Pet(String initialName) {
+        name = initialName;
+        age = 0;
+        weight = 0;
+    }
+
+    public void setName(String newName) {
+        name = newName; //age and weight are unchanged.
+    }
+
+
+
+
+    public Pet(int initialAge)
+    {
+        name = "No name yet.";
+        weight = 0;
+        if (initialAge < 0)
+        {
+            System.out.println("Error: Negative age.");
+            System.exit(0);
+        }
+        else
+            age = initialAge;
+    }
+    public void setAge(int newAge)
+    {
+        if (newAge < 0)
+        {
+            System.out.println("Error: Negative age.");
+            System.exit(0);
+        }
+        else
+            age = newAge;
+        //name and weight are unchanged.
+    }
+
+    public Pet(double initialWeight)
+    {
+        name = "No name yet";
+        age = 0;
+        if (initialWeight < 0)
+        {
+            System.out.println("Error: Negative weight.");
+            System.exit(0);
+        }else weight = initialWeight;
+    }
+
+    public void setWeight(double newWeight)
+    {
+        if (newWeight < 0)
+        {
+            System.out.println("Error: Negative weight.");
+            System.exit(0);
+        }
+        else
+            weight = newWeight; //name and age are unchanged.
+    }
+
+    public String getName()
+    {
+        return name;
+    }
+    public int getAge()
+    {
+        return age; }
+    public double getWeight()
+    {
+        return weight;
+    }
+    public void writeOutput() {
+        System.out.println("Name: " + name);
+        System.out.println("Age: " + age + " years");
+        System.out.println("Weight: " + weight + " pounds");
+    }
+
+}
\ No newline at end of file
diff --git a/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_11/LinkedQueue.java b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_11/LinkedQueue.java
new file mode 100644
index 0000000..d816584
--- /dev/null
+++ b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_11/LinkedQueue.java
@@ -0,0 +1,58 @@
+package me.alex4386.gachon.sw14462.day25.ex14_11;
+
+import java.util.Iterator;
+import java.util.LinkedList;
+
+public class LinkedQueue<T extends Object> extends LinkedList<T> {
+
+    private int front;
+    private int count;
+
+    public LinkedQueue() {
+        super();
+        front = 0;
+        count = 0;
+    }
+
+    public void addToQueue(T item) {
+        this.add(item);
+        this.count++;
+    }
+
+    public T removeFromQueue() {
+        if (this.count == 0) {
+            return null;
+        }
+        this.count--;
+        return this.get(this.front++);
+    }
+
+    public boolean isEmpty() {
+        return this.count == 0;
+    }
+
+    public Iterator<T> iterator() {
+        return new Iterator<T>() {
+            private int index = front;
+            private int count = 0;
+
+            @Override
+            public boolean hasNext() {
+                return count < LinkedQueue.this.count;
+            }
+
+            @Override
+            public T next() {
+                if (!this.hasNext()) return null;
+
+                count++;
+                return LinkedQueue.this.get(index++);
+            }
+        };
+    }
+
+    @Override
+    public int size() {
+        return this.count;
+    }
+}
diff --git a/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_11/Main.java b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_11/Main.java
new file mode 100644
index 0000000..17f9448
--- /dev/null
+++ b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_11/Main.java
@@ -0,0 +1,56 @@
+package me.alex4386.gachon.sw14462.day25.ex14_11;
+
+import java.util.Iterator;
+
+public class Main {
+    public static void main(String[] args) {
+        LinkedQueue<Integer> queue = new LinkedQueue<>();
+
+        for (int i = 0; i < 10; i++) {
+            System.out.println("Pushing "+i+" to queue");
+            queue.addToQueue(i);
+
+            System.out.println("Current Queue Content:");
+            printIterator(queue.iterator());
+            System.out.println();
+        }
+
+        for (int i = 0; i < 5; i++) {
+            int value = queue.removeFromQueue().intValue();
+            System.out.println("Popping "+value+" from queue");
+
+            System.out.println("Current Queue Content:");
+            printIterator(queue.iterator());
+            System.out.println();
+        }
+
+        for (int i = 0; i < 5; i++) {
+            System.out.println("Pushing "+i+" to queue");
+            queue.addToQueue(i);
+
+            System.out.println("Current Queue Content:");
+            printIterator(queue.iterator());
+            System.out.println();
+        }
+
+
+        while (!queue.isEmpty()) {
+            int value = queue.removeFromQueue().intValue();
+            System.out.println("Popping "+value+" from queue");
+
+            System.out.println("Current Queue Content:");
+            printIterator(queue.iterator());
+            System.out.println();
+        }
+    }
+
+    public static<T extends Object> void printIterator(Iterator<T> iter) {
+        boolean first = true;
+        while (iter.hasNext()) {
+            if (!first) System.out.print(", ");
+            first = false;
+            System.out.print(iter.next());
+        }
+        System.out.println();
+    }
+}
diff --git a/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_1a/Main.java b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_1a/Main.java
new file mode 100644
index 0000000..28e1a84
--- /dev/null
+++ b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_1a/Main.java
@@ -0,0 +1,58 @@
+package me.alex4386.gachon.sw14462.day25.ex14_1a;
+
+import java.util.ArrayList;
+
+public class Main {
+    public static ArrayList<String> arrayToList(String[] array) {
+        ArrayList<String> list = new ArrayList<String>();
+        for (String item : array) {
+            list.add(item);
+        }
+        return list;
+    }
+
+    public static void removeFromArrayList(ArrayList<String> list, String s) {
+        for (int i = 0; i < list.size(); i++) {
+            if (list.get(i).equals(s)) {
+                list.remove(i);
+                i--;
+            }
+        }
+    }
+
+    public static <T extends Object> void printArray(T[] array) {
+        boolean first = true;
+        for (Object item : array) {
+            if (!first) System.out.print(", ");
+            first = false;
+            System.out.print(item);
+        }
+        System.out.println();
+    }
+
+    public static <U, T extends Iterable<U>> void printIterable(T iter) {
+        boolean first = true;
+        for (Object item : iter) {
+            if (!first) System.out.print(", ");
+            first = false;
+            System.out.print(item);
+        }
+        System.out.println();
+    }
+
+    public static void main(String[] args) {
+        String[] array = {"a", "b", "c", "d", "e"};
+        System.out.println("Array: ");
+        printArray(array);
+
+
+        System.out.println("ArrayList: ");
+        ArrayList<String> list = arrayToList(array);
+        printIterable(list);
+
+        System.out.println("Removed \"c\" from ArrayList: ");
+        removeFromArrayList(list, "c");
+        printIterable(list);
+    }
+
+}
diff --git a/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_1b/Main.java b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_1b/Main.java
new file mode 100644
index 0000000..6a01d0c
--- /dev/null
+++ b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_1b/Main.java
@@ -0,0 +1,7 @@
+package me.alex4386.gachon.sw14462.day25.ex14_1b;
+
+public class Main {
+    public static void main(String[] args) {
+        ScoreReaderTest.main(args);
+    }
+}
diff --git a/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_1b/ScoreReader.java b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_1b/ScoreReader.java
new file mode 100644
index 0000000..e0e9296
--- /dev/null
+++ b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_1b/ScoreReader.java
@@ -0,0 +1,39 @@
+package me.alex4386.gachon.sw14462.day25.ex14_1b;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class ScoreReader {
+
+    private ArrayList<Integer> scores = new ArrayList<Integer>();
+
+    public ScoreReader() {
+    }
+
+    public void addScore(int score) {
+        this.scores.add(score);
+    }
+
+    public double getAverage() {
+        double sum = 0;
+        for (Integer score : this.scores) {
+            sum += score;
+        }
+
+        return sum / this.scores.size();
+    }
+
+    public List<Integer> getScoresAboveAverage() {
+        double average = this.getAverage();
+
+        List<Integer> data = new ArrayList<Integer>();
+        for (Integer score : this.scores) {
+            if (score > average) {
+                data.add(score);
+            }
+        }
+
+        return data;
+    }
+}
+
diff --git a/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_1b/ScoreReaderTest.java b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_1b/ScoreReaderTest.java
new file mode 100644
index 0000000..b4b48f8
--- /dev/null
+++ b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_1b/ScoreReaderTest.java
@@ -0,0 +1,40 @@
+package me.alex4386.gachon.sw14462.day25.ex14_1b;
+
+import java.util.Iterator;
+import java.util.List;
+import java.util.Scanner;
+
+public class ScoreReaderTest {
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+
+        ScoreReader scoreReader = new ScoreReader();
+
+        int i = 0;
+        while (true) {
+            System.out.print("Enter the score of student " + (i + 1) + " (Enter -1 to stop) : ");
+            int score = scanner.nextInt();
+            if (score < 0) break;
+
+            scoreReader.addScore(score);
+            i++;
+        }
+
+        System.out.println("Average score: " + scoreReader.getAverage());
+        List<Integer> scoresAboveAverage = scoreReader.getScoresAboveAverage();
+        System.out.print("Scores above average: ");
+        printIterable(scoresAboveAverage);
+
+        System.out.println();
+    }
+
+    public static <U, T extends Iterable<U>> void printIterable(T iter) {
+        boolean first = true;
+        for (Object item : iter) {
+            if (!first) System.out.print(", ");
+            first = false;
+            System.out.print(item);
+        }
+        System.out.println();
+    }
+}
diff --git a/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_2a/HashMapDemo.java b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_2a/HashMapDemo.java
new file mode 100644
index 0000000..71a23c1
--- /dev/null
+++ b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_2a/HashMapDemo.java
@@ -0,0 +1,35 @@
+package me.alex4386.gachon.sw14462.day25.ex14_2a;
+
+import java.util.HashMap;
+
+public class HashMapDemo {
+    public static void main(String[] args) {
+        HashMap<String, Integer> mountains = new HashMap<>();
+
+        mountains.put("Everest", 29029);
+        mountains.put("K2", 28251);
+        mountains.put("Kangchenjunga", 28169);
+        mountains.put("Denali", 20335);
+
+        printMap(mountains);
+
+        System.out.println("Denali in the map: " + mountains.containsKey("Denali"));
+        System.out.println();
+        System.out.println("Changing height of Denali");
+        mountains.put("Denali", 20320);
+        printMap(mountains);
+
+        System.out.println("Removing Kangchenjunga");
+        mountains.remove("Kangchenjunga");
+        printMap(mountains);
+    }
+
+    public static void printMap(HashMap<String, Integer> map) {
+        System.out.println("Map contains:");
+        for (String mountainName : map.keySet()) {
+            Integer height = map.get(mountainName);
+            System.out.println(mountainName + " -> " + height.intValue() + "feet.");
+        }
+        System.out.println();
+    }
+}
diff --git a/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_2a/HashSetDemo.java b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_2a/HashSetDemo.java
new file mode 100644
index 0000000..1222d49
--- /dev/null
+++ b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_2a/HashSetDemo.java
@@ -0,0 +1,28 @@
+package me.alex4386.gachon.sw14462.day25.ex14_2a;
+
+import java.util.HashSet;
+
+public class HashSetDemo {
+    public static void main(String[] args) {
+        HashSet<Integer> intSet = new HashSet<>();
+
+        intSet.add(2);
+        intSet.add(7);
+        intSet.add(7); // This is ignored
+                       // since 7 is alread in the set
+        intSet.add(3);
+        printSet(intSet);
+        intSet.remove(3);
+        printSet(intSet);
+        System.out.println("Set contains 2: "+intSet.contains(2));
+        System.out.println("Set contains 3: "+intSet.contains(3));
+    }
+
+    public static void printSet(HashSet<Integer> intSet) {
+        System.out.println("The set contains:");
+        for (Object obj : intSet.toArray()) {
+            Integer num = (Integer) obj;
+            System.out.println(num.intValue());
+        }
+    }
+}
diff --git a/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_2a/Main.java b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_2a/Main.java
new file mode 100644
index 0000000..da25367
--- /dev/null
+++ b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_2a/Main.java
@@ -0,0 +1,8 @@
+package me.alex4386.gachon.sw14462.day25.ex14_2a;
+
+public class Main {
+    public static void main(String[] args) {
+        HashSetDemo.main(args);
+        HashMapDemo.main(args);
+    }
+}
diff --git a/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_2b/Main.java b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_2b/Main.java
new file mode 100644
index 0000000..e8eba48
--- /dev/null
+++ b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_2b/Main.java
@@ -0,0 +1,48 @@
+package me.alex4386.gachon.sw14462.day25.ex14_2b;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Set;
+
+public class Main {
+    public static <T> HashSet<T> arrayToHashSet(T[] array) {
+        HashSet<T> set = new HashSet<>();
+        for (T item : array) {
+            set.add(item);
+        }
+        return set;
+    }
+
+    public static <T extends Object> void removeFromHashSet(HashSet<T> set, T key) {
+        set.remove(key);
+    }
+
+    public static <U, T extends Iterable<U>> void printIterable(T iter) {
+        boolean first = true;
+        for (Object item : iter) {
+            if (!first) System.out.print(", ");
+            first = false;
+            System.out.print(item);
+        }
+        System.out.println();
+    }
+
+    public static <T extends Object> void printSet(Set<T> set) {
+        printIterable(set);
+    }
+
+    public static void main(String[] args) {
+        String[] array = {"a", "b", "c", "d", "e"};
+        System.out.println("Array: ");
+        printIterable(Arrays.asList(array));
+
+        HashSet<String> set = arrayToHashSet(array);
+        System.out.println("HashSet: ");
+        printSet(set);
+
+        System.out.println("HashSet after removing c: ");
+        removeFromHashSet(set, "c");
+        printSet(set);
+    }
+}
diff --git a/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_2c/Main.java b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_2c/Main.java
new file mode 100644
index 0000000..b089113
--- /dev/null
+++ b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_2c/Main.java
@@ -0,0 +1,58 @@
+package me.alex4386.gachon.sw14462.day25.ex14_2c;
+
+import java.util.LinkedList;
+
+public class Main {
+    public static LinkedList<String> arrayToLinkedList(String[] array) {
+        LinkedList<String> list = new LinkedList<String>();
+        for (String item : array) {
+            list.add(item);
+        }
+        return list;
+    }
+
+    public static void removeFromLinkedList(LinkedList<String> list, String s) {
+        for (int i = 0; i < list.size(); i++) {
+            if (list.get(i).equals(s)) {
+                list.remove(i);
+                i--;
+            }
+        }
+    }
+
+    public static <T extends Object> void printArray(T[] array) {
+        boolean first = true;
+        for (Object item : array) {
+            if (!first) System.out.print(", ");
+            first = false;
+            System.out.print(item);
+        }
+        System.out.println();
+    }
+
+    public static <U, T extends Iterable<U>> void printIterable(T iter) {
+        boolean first = true;
+        for (Object item : iter) {
+            if (!first) System.out.print(", ");
+            first = false;
+            System.out.print(item);
+        }
+        System.out.println();
+    }
+
+    public static void main(String[] args) {
+        String[] array = {"a", "b", "c", "d", "e"};
+        System.out.println("Array: ");
+        printArray(array);
+
+
+        System.out.println("ArrayList: ");
+        LinkedList<String> list = arrayToLinkedList(array);
+        printIterable(list);
+
+        System.out.println("Removed \"c\" from ArrayList: ");
+        removeFromLinkedList(list, "c");
+        printIterable(list);
+    }
+
+}
diff --git a/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_5/Main.java b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_5/Main.java
new file mode 100644
index 0000000..8327e2e
--- /dev/null
+++ b/src/main/java/me/alex4386/gachon/sw14462/day25/ex14_5/Main.java
@@ -0,0 +1,26 @@
+package me.alex4386.gachon.sw14462.day25.ex14_5;
+
+import java.util.HashMap;
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+        HashMap<Integer, Integer> counts = new HashMap<>();
+
+        while(true) {
+            int value = scanner.nextInt();
+            if (value == -1) break;
+
+            if (counts.containsKey(value)) {
+                counts.put(value, counts.get(value) + 1);
+            } else {
+                counts.put(value, 1);
+            }
+        }
+
+        for (Integer key : counts.keySet()) {
+            System.out.println("The number "+ key + " occurs " + counts.get(key) + " times.");
+        }
+    }
+}