feat: implement State class with population management and exception handling

Author: nia-source

lesson_16/objects/objects_app/src/main/java/com/codedifferently/lesson16/Lesson16.java

@@ -13,3 +13,4 @@ public static void main(String[] args) {
     application.run(args);
   }
 }
+

lesson_16/objects/objects_app/src/main/states/PopulationException.java

@@ -0,0 +1,7 @@
+package com.codedifferently.lesson16.states;
+
+  class PopulationTooLowException extends Exception {
+    public PopulationTooLowException(String message) {
+        super(message);
+    }
+}

lesson_16/objects/objects_app/src/main/states/State.java

@@ -0,0 +1,41 @@
+package com.codedifferently.lesson16.states;
+import java.util.ArrayList;
+
+  
+  public class State {
+    private String name;
+    private String capital;
+    private int population;
+    private double area;
+    private Region region;
+    private ArrayList<String> majorCities;
+
+    enum Region {
+  NORTHEAST, MIDWEST, SOUTH, WEST, PACIFIC 
+  }
+    public State(String name, String capital, int population, double area, Region region) {
+        this.name = name;
+        this.capital = capital;
+        this.population = population;
+        this.area = area;
+        this.region = region;
+        this.majorCities = new ArrayList<>();
+    }
+    public void updatePopulation(int newPopulation) throws PopulationTooLowException {
+        if (newPopulation < 10000) {
+            throw new PopulationTooLowException("Population too low for a state!");
+        }
+        this.population = newPopulation;
+        System.out.println("Population updated to " + newPopulation);
+    }
+    public void addMajorCity(String city) {
+        majorCities.add(city);
+        System.out.println(city = "added to major cities of " + name);
+    }
+    public void listMajorCities() {
+        System.out.println("Major cities in " + name + ":");
+        for (String city : majorCities) {
+            System.out.println("- " + city);
+        }
+    }
+  }

lesson_16/objects/objects_app/src/test/java/com/codedifferently/lesson16/states/StateTest.java

@@ -0,0 +1,4 @@
+package com.codedifferently.lesson16.states;
+public class StateTest {
+    
+}