added task solution

pom.xml

@@ -9,7 +9,7 @@
     <version>1.0-SNAPSHOT</version>
 
     <properties>
-        <jdk.version>17</jdk.version>
+        <jdk.version>11</jdk.version>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
         <maven.checkstyle.plugin.configLocation>

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 +1,16 @@
 package core.basesyntax;
 
 public class PasswordValidator {
-    public void validate(String password, String repeatPassword) {
-        //write your code here
+    public static final int MIN_LENGTH = 10;
+
+    public void validate(
+            String password,
+            String repeatPassword
+    ) throws PasswordValidationException {
+        if (password == null
+                || !password.equals(repeatPassword)
+                || password.length() < MIN_LENGTH) {
+            throw new PasswordValidationException("Wrong passwords");
+        }
     }
 }

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

@@ -1,8 +1,15 @@
 package core.basesyntax;
 
 public class UserService {
+    private final PasswordValidator passwordValidator = new PasswordValidator();
+
     public void registerUser(User user) {
-        //write your code here
+        try {
+            passwordValidator.validate(user.getPassword(), user.getRepeatPassword());
+            saveUser(user);
+        } catch (PasswordValidationException e) {
+            System.out.println("Your passwords are incorrect. Try again.");
+        }
     }
 
     public void saveUser(User user) {