exception handling and basic file operations in Java

src/main/java/org/Exceptions/RuntimeExceptionDemo.java

@@ -19,44 +19,58 @@ public class RuntimeExceptionDemo {
     //nullPointerException
     //IllegalArgumentException
     public static void validateEmail(UserEntity user) {
+        try {
+            String email = user.getEmail();
 
-        String email = user.getEmail();
+            String emailRegex = "^[A-Za-z0-9+_.-]+@[A-Za-z0-9.-]+$";
 
-        String emailRegex = "^[A-Za-z0-9+_.-]+@[A-Za-z0-9.-]+$";
+            if (!Pattern.matches(emailRegex, email)) {
+                throw new IllegalArgumentException("Invalid email format");
+            }
 
-        if (!Pattern.matches(emailRegex, email)) {
-            throw new IllegalArgumentException("Invalid email format");
+            System.out.println("User email is valid");
+        } catch (NullPointerException e) {
+            System.out.println("Error: email is null - " + e.getMessage());
+        } catch (IllegalArgumentException e) {
+            System.out.println("Error: " + e.getMessage());
         }
-
-        System.out.println("User email is valid");
     }
 
     // ArithmeticException
     public static void calculatePayment(int totalAmount, int installmentCount) {
+        try {
+            int payment = totalAmount / installmentCount;
 
-        int payment = totalAmount / installmentCount;
-
-        System.out.println("Each installment : " + payment);
+            System.out.println("Each installment : " + payment);
+        } catch (ArithmeticException e) {
+            System.out.println("Error: cannot divide by zero - " + e.getMessage());
+        }
     }
 
     // NumberFormatException
     public static void convertUserAge(String ageInput) {
+        try {
+            int age = Integer.parseInt(ageInput);
 
-        int age = Integer.parseInt(ageInput);
-
-        System.out.println("User age: " + age);
+            System.out.println("User age: " + age);
+        } catch (NumberFormatException e) {
+            System.out.println("Error: invalid number format - " + e.getMessage());
+        }
     }
 
 //    IllegalStateException
     public static void completeRegistration(UserEntity user) {
+        try {
+            if (user.getDateOfBirth() == null) {
+                throw new IllegalStateException(
+                        "Registration cannot be completed. Date of birth is missing."
+                );
+            }
 
-        if (user.getDateOfBirth() == null) {
-            throw new IllegalStateException(
-                    "Registration cannot be completed. Date of birth is missing."
-            );
+            System.out.println("Registration completed");
+        } catch (IllegalStateException e) {
+            System.out.println("Error: " + e.getMessage());
         }
-
-        System.out.println("Registration completed");
     }
 
 }