Implement password validation.

src/main/java/core/basesyntax/PasswordValidationException.java

@@ -1,3 +1,7 @@
 package core.basesyntax;
 
-//write your code here
+public class PasswordValidationException extends Exception {
+    public PasswordValidationException(String message) {
+        super(message);
+    }
+}

src/main/java/core/basesyntax/PasswordValidator.java

@@ -1,7 +1,13 @@
 package core.basesyntax;
 
 public class PasswordValidator {
-    public void validate(String password, String repeatPassword) {
-        //write your code here
+    private static final int MIN_PASSWORD_LENGTH = 10;
+
+    public void validate(String password, String repeatPassword)
+            throws PasswordValidationException {
+        if (null == password || password.length() < MIN_PASSWORD_LENGTH
+                || !password.equals(repeatPassword)) {
+            throw new PasswordValidationException("Wrong passwords");
+        }
     }
 }

src/main/java/core/basesyntax/UserService.java

@@ -2,7 +2,13 @@
 
 public class UserService {
     public void registerUser(User user) {
-        //write your code here
+        PasswordValidator validator = new PasswordValidator();
+        try {
+            validator.validate(user.getPassword(), user.getRepeatPassword());
+            saveUser(user);
+        } catch (PasswordValidationException e) {
+            System.out.println("Your passwords are incorrect. Try again.");
+        }
     }
 
     public void saveUser(User user) {