diff --git a/JavaCourse/src/main/java/com/rinftech/Ex10.java b/JavaCourse/src/main/java/com/rinftech/Ex10.java
new file mode 100644
index 0000000..3749a91
--- /dev/null
+++ b/JavaCourse/src/main/java/com/rinftech/Ex10.java
@@ -0,0 +1,32 @@
+package com.rinftech;
+
+import java.util.*;
+
+public class Ex10 {
+    public static void main(String[] args) {
+        String[] input = {"eat", "tea", "tan", "ate", "nat", "bat", "listen", "silent", "enlist", "hello", "world", "dlrow"};
+        Map<String, List<String>> anagrams = groupAnagrams(input);
+
+        for(List<String> anagram:anagrams.values())
+        {
+            System.out.println(anagram);
+        }
+    }
+
+    public static Map<String, List<String>> groupAnagrams(String[] input) {
+        Map<String, List<String>> anagrams = new HashMap<>();
+
+        for (String str : input) {
+            char[] arrChar = str.toCharArray();
+            Arrays.sort(arrChar);
+            String sortedLettersWord = new String(arrChar);
+
+            if (!anagrams.containsKey(sortedLettersWord)) {
+                anagrams.put(sortedLettersWord, new ArrayList<>());
+            }
+            anagrams.get(sortedLettersWord).add(str);
+        }
+
+        return anagrams;
+    }
+}
\ No newline at end of file
diff --git a/JavaCourse/src/main/java/com/rinftech/Exercices/Ex1.java b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex1.java
new file mode 100644
index 0000000..1995e74
--- /dev/null
+++ b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex1.java
@@ -0,0 +1,34 @@
+package com.rinftech.Exercices;
+
+public class Ex1
+{
+    private static int sumOfDigits(int n)
+    {
+        int sum = 0;
+
+        while(n != 0)
+        {
+            sum += n%10;
+            n /= 10;
+        }
+
+        return sum;
+    }
+
+    public static void main(String[] args)
+    {
+        int n, sum;
+
+        n = 8733;
+        sum = sumOfDigits(n);
+        System.out.println("Sum of digits of " + n + " = " + sum);
+
+        n = 123456789;
+        sum = sumOfDigits(n);
+        System.out.println("Sum of digits of " + n + " = " + sum);
+
+        n = 29293129;
+        sum = sumOfDigits(n);
+        System.out.println("Sum of digits of " + n + " = " + sum);
+    }
+}
diff --git a/JavaCourse/src/main/java/com/rinftech/Exercices/Ex2.java b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex2.java
new file mode 100644
index 0000000..ea40dd7
--- /dev/null
+++ b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex2.java
@@ -0,0 +1,39 @@
+package com.rinftech.Exercices;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class Ex2
+{
+    private static Map<String,Integer> countCharacters(String s)
+    {
+        Map<String,Integer> counterMap = new HashMap<>();
+        counterMap.put("Letters", 0);
+        counterMap.put("Spaces", 0);
+        counterMap.put("Numbers", 0);
+
+        for(int i = 0;i<s.length();i++)
+        {
+            char c = s.charAt(i);
+            if(c == ' ')
+            {
+                counterMap.put("Spaces", counterMap.get("Spaces") + 1);
+            }
+            else if ((c>='a' && c<='z') || (c>='A' && c<='Z'))
+            {
+                counterMap.put("Letters",counterMap.get("Letters") + 1);
+            }
+            else if(c>='0' && c<='9')
+            {
+                counterMap.put("Numbers",counterMap.get("Numbers") +1);
+            }
+        }
+        return counterMap;
+    }
+
+    public static void main(String[] args)
+    {
+        String input = "The quick brown fox jumps over 42 lazy dogs";
+        System.out.println("String statistics: " + countCharacters(input));
+    }
+}
diff --git a/JavaCourse/src/main/java/com/rinftech/Exercices/Ex3/Employee.java b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex3/Employee.java
new file mode 100644
index 0000000..77eaf38
--- /dev/null
+++ b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex3/Employee.java
@@ -0,0 +1,22 @@
+package com.rinftech.Exercices.Ex3;
+
+public class Employee extends Person
+{
+    private int employeeId;
+    private String jobTitle;
+
+    public Employee(String firstName, String lastName, int employeeId, String jobTitle) {
+        super(firstName, lastName);
+        this.employeeId = employeeId;
+        this.jobTitle = jobTitle;
+    }
+
+    public int getEmployeeId() {
+        return employeeId;
+    }
+
+    @Override
+    public String getLastName() {
+        return super.getLastName() + ", jobTitle: " + this.jobTitle;
+    }
+}
diff --git a/JavaCourse/src/main/java/com/rinftech/Exercices/Ex3/Ex3.java b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex3/Ex3.java
new file mode 100644
index 0000000..1215b3c
--- /dev/null
+++ b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex3/Ex3.java
@@ -0,0 +1,13 @@
+package com.rinftech.Exercices.Ex3;
+
+public class Ex3
+{
+    public static void main(String[] args)
+    {
+        Person person = new Person("John", "Doe");
+        System.out.println("Person " + person.getFirstName() + " " + person.getLastName());
+
+        Employee employee = new Employee("Jane","Doe",1234,"JobTitle");
+        System.out.println("Employee " + employee.getFirstName() + " " + employee.getLastName());
+    }
+}
diff --git a/JavaCourse/src/main/java/com/rinftech/Exercices/Ex3/Person.java b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex3/Person.java
new file mode 100644
index 0000000..ec6bc7a
--- /dev/null
+++ b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex3/Person.java
@@ -0,0 +1,20 @@
+package com.rinftech.Exercices.Ex3;
+
+public class Person
+{
+    private String firstName;
+    private String lastName;
+
+    public Person(String firstName, String lastName) {
+        this.firstName = firstName;
+        this.lastName = lastName;
+    }
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+}
diff --git a/JavaCourse/src/main/java/com/rinftech/Exercices/Ex4/Car.java b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex4/Car.java
new file mode 100644
index 0000000..bb8c331
--- /dev/null
+++ b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex4/Car.java
@@ -0,0 +1,31 @@
+package com.rinftech.Exercices.Ex4;
+
+public class Car extends Vehicle
+{
+    private int seats;
+
+    public Car(String make, String model, int year, String fuelType, int seats) {
+        super(make, model, year, fuelType);
+        this.seats = seats;
+    }
+
+    public int getSeats() {
+        return seats;
+    }
+
+    public void setSeats(int seats) {
+        this.seats = seats;
+    }
+
+    @Override
+    public double calculateFuelEfficiency(double distance, double fuelConsumed) {
+        return 5.4;
+    }
+
+    @Override
+    public String toString() {
+        return "Car{" +
+                "seats=" + seats +
+                '}';
+    }
+}
diff --git a/JavaCourse/src/main/java/com/rinftech/Exercices/Ex4/Ex4.java b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex4/Ex4.java
new file mode 100644
index 0000000..75174e0
--- /dev/null
+++ b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex4/Ex4.java
@@ -0,0 +1,19 @@
+package com.rinftech.Exercices.Ex4;
+
+public class Ex4
+{
+    public static void main(String[] args)
+    {
+        Vehicle vehicle = new Vehicle("SomeMake","SomeModel",2000,"SomeFuelType");
+        System.out.println(vehicle);
+
+        Car car = new Car("CarMake","CarModel",2002,"CarFuelType",5);
+        System.out.println("Car's fuel efficiency: " + car.calculateFuelEfficiency(2.3,2));
+
+        Truck truck = new Truck("TruckMake","TruckModel",2004,"TruckFuelType",2500);
+        System.out.println("Truck's max speed: " + truck.getMaxSpeed());
+
+        Motorcycle motorcycle = new Motorcycle("Kawasaki","Ninja H2R",2022,"Diesel",false);
+        System.out.println("Motorcycle's distance: " + motorcycle.calculateDistance(25.5,30));
+    }
+}
diff --git a/JavaCourse/src/main/java/com/rinftech/Exercices/Ex4/Motorcycle.java b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex4/Motorcycle.java
new file mode 100644
index 0000000..8afd71b
--- /dev/null
+++ b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex4/Motorcycle.java
@@ -0,0 +1,31 @@
+package com.rinftech.Exercices.Ex4;
+
+public class Motorcycle extends Vehicle
+{
+    private boolean hasSidecar;
+
+    public Motorcycle(String make, String model, int year, String fuelType, boolean hasSidecar) {
+        super(make, model, year, fuelType);
+        this.hasSidecar = hasSidecar;
+    }
+
+    public boolean isHasSidecar() {
+        return hasSidecar;
+    }
+
+    public void setHasSidecar(boolean hasSidecar) {
+        this.hasSidecar = hasSidecar;
+    }
+
+    @Override
+    public double calculateDistance(double speed, double time) {
+        return 27.5;
+    }
+
+    @Override
+    public String toString() {
+        return "Motorcycle{" +
+                "hasSidecar=" + hasSidecar +
+                '}';
+    }
+}
\ No newline at end of file
diff --git a/JavaCourse/src/main/java/com/rinftech/Exercices/Ex4/Truck.java b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex4/Truck.java
new file mode 100644
index 0000000..ea4cf9d
--- /dev/null
+++ b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex4/Truck.java
@@ -0,0 +1,31 @@
+package com.rinftech.Exercices.Ex4;
+
+public class Truck extends Vehicle
+{
+    private double capacity;
+
+    public Truck(String make, String model, int year, String fuelType, double capacity) {
+        super(make, model, year, fuelType);
+        this.capacity = capacity;
+    }
+
+    public double getCapacity() {
+        return capacity;
+    }
+
+    public void setCapacity(double capacity) {
+        this.capacity = capacity;
+    }
+
+    @Override
+    public double getMaxSpeed() {
+        return 100;
+    }
+
+    @Override
+    public String toString() {
+        return "Truck{" +
+                "capacity=" + capacity +
+                '}';
+    }
+}
\ No newline at end of file
diff --git a/JavaCourse/src/main/java/com/rinftech/Exercices/Ex4/Vehicle.java b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex4/Vehicle.java
new file mode 100644
index 0000000..7dc2cfa
--- /dev/null
+++ b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex4/Vehicle.java
@@ -0,0 +1,73 @@
+package com.rinftech.Exercices.Ex4;
+
+public class Vehicle
+{
+    private String make;
+    private String model;
+    private int year;
+    private String fuelType;
+
+    public Vehicle(String make, String model, int year, String fuelType) {
+        this.make = make;
+        this.model = model;
+        this.year = year;
+        this.fuelType = fuelType;
+    }
+
+    public String getMake() {
+        return make;
+    }
+
+    public void setMake(String make) {
+        this.make = make;
+    }
+
+    public String getModel() {
+        return model;
+    }
+
+    public void setModel(String model) {
+        this.model = model;
+    }
+
+    public int getYear() {
+        return year;
+    }
+
+    public void setYear(int year) {
+        this.year = year;
+    }
+
+    public String getFuelType() {
+        return fuelType;
+    }
+
+    public void setFuelType(String fuelType) {
+        this.fuelType = fuelType;
+    }
+
+    public double calculateFuelEfficiency(double distance, double fuelConsumed)
+    {
+        return distance / fuelConsumed;
+    }
+
+    public double calculateDistance(double speed, double time)
+    {
+        return speed * time;
+    }
+
+    public double getMaxSpeed()
+    {
+        return 0;
+    }
+
+    @Override
+    public String toString() {
+        return "Vehicle{" +
+                "make='" + make + '\'' +
+                ", model='" + model + '\'' +
+                ", year=" + year +
+                ", fuelType='" + fuelType + '\'' +
+                '}';
+    }
+}
diff --git a/JavaCourse/src/main/java/com/rinftech/Exercices/Ex5.java b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex5.java
new file mode 100644
index 0000000..b43d374
--- /dev/null
+++ b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex5.java
@@ -0,0 +1,32 @@
+package com.rinftech.Exercices;
+
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+public class Ex5
+{
+    public static void main(String[] args)
+    {
+        String[] firstArray = { "Python", "Java", "GoLang", "Lisp" };
+        String[] secondArray = { "Java", "C++", "Apples", "Hamburger", "Lisp"};
+
+        Set<String> firstSet = new HashSet<>();
+        Set<String> secondSet = new HashSet<>();
+
+        for(String str:firstArray)
+        {
+            firstSet.add(str);
+        }
+
+        for (String str:secondArray)
+        {
+            secondSet.add(str);
+        }
+
+        firstSet.retainAll(secondSet);
+
+        System.out.println("Common elements between the arrays: " + firstSet);
+
+    }
+}
diff --git a/JavaCourse/src/main/java/com/rinftech/Exercices/Ex6/Circle.java b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex6/Circle.java
new file mode 100644
index 0000000..8e3f9ce
--- /dev/null
+++ b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex6/Circle.java
@@ -0,0 +1,23 @@
+package com.rinftech.Exercices.Ex6;
+
+public class Circle extends Shape
+{
+    private double radius;
+
+    public Circle(double radius) {
+        this.radius = radius;
+    }
+
+    public double getRadius() {
+        return radius;
+    }
+
+    public void setRadius(double radius) {
+        this.radius = radius;
+    }
+
+    @Override
+    public double calculateArea() {
+        return Math.PI * radius * radius;
+    }
+}
diff --git a/JavaCourse/src/main/java/com/rinftech/Exercices/Ex6/Ex6.java b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex6/Ex6.java
new file mode 100644
index 0000000..9e58975
--- /dev/null
+++ b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex6/Ex6.java
@@ -0,0 +1,15 @@
+package com.rinftech.Exercices.Ex6;
+
+public class Ex6
+{
+    public static void main(String[] args)
+    {
+        Circle circle = new Circle(10);
+        Rectangle rectangle = new Rectangle(4, 6);
+        Triangle triangle = new Triangle(10,6,8);
+
+        System.out.println("Circle's area = " + circle.calculateArea());
+        System.out.println("Rectangle's area = " + rectangle.calculateArea());
+        System.out.println("Triangle's area = " +  triangle.calculateArea());
+    }
+}
diff --git a/JavaCourse/src/main/java/com/rinftech/Exercices/Ex6/Rectangle.java b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex6/Rectangle.java
new file mode 100644
index 0000000..21df1ac
--- /dev/null
+++ b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex6/Rectangle.java
@@ -0,0 +1,32 @@
+package com.rinftech.Exercices.Ex6;
+
+public class Rectangle extends Shape
+{
+    private double length, width;
+
+    public Rectangle(double length, double width) {
+        this.length = length;
+        this.width = width;
+    }
+
+    public double getLength() {
+        return length;
+    }
+
+    public void setLength(double length) {
+        this.length = length;
+    }
+
+    public double getWidth() {
+        return width;
+    }
+
+    public void setWidth(double width) {
+        this.width = width;
+    }
+
+    @Override
+    public double calculateArea() {
+        return length * width;
+    }
+}
diff --git a/JavaCourse/src/main/java/com/rinftech/Exercices/Ex6/Shape.java b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex6/Shape.java
new file mode 100644
index 0000000..0974767
--- /dev/null
+++ b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex6/Shape.java
@@ -0,0 +1,9 @@
+package com.rinftech.Exercices.Ex6;
+
+public class Shape
+{
+    public double calculateArea()
+    {
+        return 0.0;
+    }
+}
diff --git a/JavaCourse/src/main/java/com/rinftech/Exercices/Ex6/Triangle.java b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex6/Triangle.java
new file mode 100644
index 0000000..66dad68
--- /dev/null
+++ b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex6/Triangle.java
@@ -0,0 +1,44 @@
+package com.rinftech.Exercices.Ex6;
+
+public class Triangle extends Shape
+{
+    private double l1, l2, l3;
+
+    public Triangle(double l1, double l2, double l3) {
+        this.l1 = l1;
+        this.l2 = l2;
+        this.l3 = l3;
+    }
+
+    public double getL1() {
+        return l1;
+    }
+
+    public void setL1(double l1) {
+        this.l1 = l1;
+    }
+
+    public double getL2() {
+        return l2;
+    }
+
+    public void setL2(double l2) {
+        this.l2 = l2;
+    }
+
+    public double getL3() {
+        return l3;
+    }
+
+    public void setL3(double l3) {
+        this.l3 = l3;
+    }
+
+    @Override
+    public double calculateArea() {
+        double s = this.l1 + this.l2 + this.l3;
+        s = s/2;
+
+        return Math.sqrt(s * (s - this.l1) * (s - this.l2) * (s - this.l3));
+    }
+}
diff --git a/JavaCourse/src/main/java/com/rinftech/Exercices/Ex7/Animal.java b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex7/Animal.java
new file mode 100644
index 0000000..94ad1a0
--- /dev/null
+++ b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex7/Animal.java
@@ -0,0 +1,14 @@
+package com.rinftech.Exercices.Ex7;
+
+public class Animal
+{
+    public void eat()
+    {
+        System.out.println("This animal eats something");
+    }
+
+    public void sound()
+    {
+        System.out.println("This animal makes a sound and it is very loud");
+    }
+}
diff --git a/JavaCourse/src/main/java/com/rinftech/Exercices/Ex7/Ex7.java b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex7/Ex7.java
new file mode 100644
index 0000000..51116d0
--- /dev/null
+++ b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex7/Ex7.java
@@ -0,0 +1,26 @@
+package com.rinftech.Exercices.Ex7;
+
+public class Ex7
+{
+    public static void main(String[] args)
+    {
+        Lion lion = new Lion();
+        Tiger tiger = new Tiger();
+        Panther panther = new Panther();
+
+        System.out.println("Lion:");
+        lion.eat();
+        lion.sound();
+        System.out.println();
+
+        System.out.println("Tiger:");
+        tiger.eat();
+        tiger.sound();
+        System.out.println();
+
+        System.out.println("Panther:");
+        panther.eat();
+        panther.sound();
+        System.out.println();
+    }
+}
diff --git a/JavaCourse/src/main/java/com/rinftech/Exercices/Ex7/Lion.java b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex7/Lion.java
new file mode 100644
index 0000000..0ee7350
--- /dev/null
+++ b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex7/Lion.java
@@ -0,0 +1,14 @@
+package com.rinftech.Exercices.Ex7;
+
+public class Lion extends Animal
+{
+    @Override
+    public void eat() {
+        System.out.println("This lion eats a gazelle");
+    }
+
+    @Override
+    public void sound() {
+        System.out.println("The lion roars. Roar :3");
+    }
+}
diff --git a/JavaCourse/src/main/java/com/rinftech/Exercices/Ex7/Panther.java b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex7/Panther.java
new file mode 100644
index 0000000..52ccfd5
--- /dev/null
+++ b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex7/Panther.java
@@ -0,0 +1,14 @@
+package com.rinftech.Exercices.Ex7;
+
+public class Panther extends Animal
+{
+    @Override
+    public void eat() {
+        System.out.println("This panther ate some meat");
+    }
+
+    @Override
+    public void sound() {
+        System.out.println("...how does a panther sound like?");
+    }
+}
diff --git a/JavaCourse/src/main/java/com/rinftech/Exercices/Ex7/Tiger.java b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex7/Tiger.java
new file mode 100644
index 0000000..58e1151
--- /dev/null
+++ b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex7/Tiger.java
@@ -0,0 +1,14 @@
+package com.rinftech.Exercices.Ex7;
+
+public class Tiger extends Animal
+{
+    @Override
+    public void eat() {
+        System.out.println("This tiger hasn't eaten anything in a while : (");
+    }
+
+    @Override
+    public void sound() {
+        System.out.println("The tiger meows. It's just a big orange cat lmao");
+    }
+}
diff --git a/JavaCourse/src/main/java/com/rinftech/Exercices/Ex8.java b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex8.java
new file mode 100644
index 0000000..92a58a5
--- /dev/null
+++ b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex8.java
@@ -0,0 +1,27 @@
+package com.rinftech.Exercices;
+
+public class Ex8
+{
+    public static void main(String[] args)
+    {
+        String[] input = {"Red", "Green", "Black", "White", "Pink"};
+        int index1 = 1;
+        int index2 = 4;
+
+        String[] output = swapStrings(input, index1, index2);
+        
+        for (int i = 0;i<output.length;i++)
+        {
+            System.out.println(output[i]);
+        }
+    }
+
+    public static String[] swapStrings(String[] input, int index1, int index2)
+    {
+        String aux = input[index1];
+        input[index1] = input[index2];
+        input[index2] = aux;
+
+        return input;
+    }
+}
diff --git a/JavaCourse/src/main/java/com/rinftech/Exercices/Ex9.java b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex9.java
new file mode 100644
index 0000000..99ae705
--- /dev/null
+++ b/JavaCourse/src/main/java/com/rinftech/Exercices/Ex9.java
@@ -0,0 +1,24 @@
+package com.rinftech.Exercices;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+public class Ex9
+{
+    public static void main(String[] args)
+    {
+        List<String> input = new ArrayList<>();
+        input = Arrays.asList("Red", "Green", "Black", "White", "Pink", "Green", "Green", "Black", "Yellow", "White");
+        String element = "Green";
+
+        getFirstAndLastOccurences(input, element);
+    }
+
+    private static void getFirstAndLastOccurences(List<String> input, String element)
+    {
+        int firstOccurence = input.indexOf(element);
+        int lastOccurence =  input.lastIndexOf(element);
+        System.out.println("First occurence = " + firstOccurence + " and last occurence = " + lastOccurence);
+    }
+}