Feature/calculator.java

Student.java

@@ -0,0 +1,34 @@
+package com.example.model;
+
+public class Student {
+    private String id;
+    private String name;
+    private int age;
+    private double gpa;
+
+    public Student() {}
+
+    public Student(String id, String name, int age, double gpa) {
+        this.id = id;
+        this.name = name;
+        this.age = age;
+        this.gpa = gpa;
+    }
+
+    public String getId() { return id; }
+    public void setId(String id) { this.id = id; }
+
+    public String getName() { return name; }
+    public void setName(String name) { this.name = name; }
+
+    public int getAge() { return age; }
+    public void setAge(int age) { this.age = age; }
+
+    public double getGpa() { return gpa; }
+    public void setGpa(double gpa) { this.gpa = gpa; }
+
+    @Override
+    public String toString() {
+        return "Student{id='" + id + "', name='" + name + "', age=" + age + ", gpa=" + gpa + "}";
+    }
+}

feature/Calculator.java

@@ -0,0 +1,29 @@
+package com.example.util;
+
+/**
+ * Simple calculator with basic operations.
+ */
+public class Calculator {
+
+    public double add(double a, double b) {
+        return a + b;
+    }
+
+    public double subtract(double a, double b) {
+        return a - b;
+    }
+
+    public double multiply(double a, double b) {
+        return a * b;
+    }
+
+    /**
+     * Division — throws IllegalArgumentException if divisor is zero.
+     */
+    public double divide(double a, double b) {
+        if (b == 0.0) {
+            throw new IllegalArgumentException("Division by zero");
+        }
+        return a / b;
+    }
+}