diff --git a/pom.xml b/pom.xml
index fc5bfeac..e4c801a0 100644
--- a/pom.xml
+++ b/pom.xml
@@ -52,9 +52,9 @@
 		</dependency>
 
 		<dependency>
-			<groupId>mysql</groupId>
-			<artifactId>mysql-connector-java</artifactId>
-			<version>8.0.33</version>
+			<groupId>com.mysql</groupId>
+			<artifactId>mysql-connector-j</artifactId>
+			<version>9.1.0</version>
 			<scope>runtime</scope>
 		</dependency>
 		<dependency>
@@ -67,6 +67,11 @@
 			<artifactId>spring-security-test</artifactId>
 			<scope>test</scope>
 		</dependency>
+		<dependency>
+			<groupId>com.h2database</groupId>
+			<artifactId>h2</artifactId>
+			<scope>test</scope>
+		</dependency>
 	</dependencies>
 
 	<build>
@@ -80,8 +85,8 @@
 				<artifactId>maven-compiler-plugin</artifactId>
 				<version>3.8.0</version>
 				<configuration>
-    					<source>1.8</source>
-    					<target>1.8</target>
+					<source>17</source>
+					<target>17</target>
 				</configuration>
 			</plugin>
 		</plugins>
diff --git a/src/main/java/com/example/bankapp/config/SecurityConfig.java b/src/main/java/com/example/bankapp/config/SecurityConfig.java
index 4dbd1572..0182ede5 100644
--- a/src/main/java/com/example/bankapp/config/SecurityConfig.java
+++ b/src/main/java/com/example/bankapp/config/SecurityConfig.java
@@ -27,7 +27,6 @@ public static PasswordEncoder passwordEncoder() {
     @Bean
     public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
         http
-                .csrf(csrf -> csrf.disable())
                 .authorizeHttpRequests(authz -> authz
                         .requestMatchers("/register").permitAll()
                         .anyRequest().authenticated()
@@ -41,12 +40,14 @@ public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Excepti
                 .logout(logout -> logout
                         .invalidateHttpSession(true)
                         .clearAuthentication(true)
-                        .logoutRequestMatcher(new AntPathRequestMatcher("/logout"))
+                        .logoutRequestMatcher(new AntPathRequestMatcher("/logout", "POST"))
                         .logoutSuccessUrl("/login?logout")
                         .permitAll()
                 )
                 .headers(headers -> headers
                         .frameOptions(frameOptions -> frameOptions.sameOrigin())
+                        .contentTypeOptions(contentTypeOptions -> {})
+                        .httpStrictTransportSecurity(hsts -> hsts.includeSubDomains(true).maxAgeInSeconds(31536000))
                 );
 
         return http.build();
diff --git a/src/main/java/com/example/bankapp/controller/BankController.java b/src/main/java/com/example/bankapp/controller/BankController.java
index 19fcded7..62724436 100644
--- a/src/main/java/com/example/bankapp/controller/BankController.java
+++ b/src/main/java/com/example/bankapp/controller/BankController.java
@@ -48,10 +48,18 @@ public String login() {
     }
 
     @PostMapping("/deposit")
-    public String deposit(@RequestParam BigDecimal amount) {
+    public String deposit(@RequestParam BigDecimal amount, Model model) {
         String username = SecurityContextHolder.getContext().getAuthentication().getName();
         Account account = accountService.findAccountByUsername(username);
-        accountService.deposit(account, amount);
+
+        try {
+            accountService.deposit(account, amount);
+        } catch (RuntimeException e) {
+            model.addAttribute("error", e.getMessage());
+            model.addAttribute("account", account);
+            return "dashboard";
+        }
+
         return "redirect:/dashboard";
     }
 
diff --git a/src/main/java/com/example/bankapp/service/AccountService.java b/src/main/java/com/example/bankapp/service/AccountService.java
index 5d7d90ec..34220e8f 100644
--- a/src/main/java/com/example/bankapp/service/AccountService.java
+++ b/src/main/java/com/example/bankapp/service/AccountService.java
@@ -12,6 +12,7 @@
 import org.springframework.security.core.userdetails.UsernameNotFoundException;
 import org.springframework.security.crypto.password.PasswordEncoder;
 import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
 
 import java.math.BigDecimal;
 import java.time.LocalDateTime;
@@ -36,19 +37,30 @@ public Account findAccountByUsername(String username) {
     }
 
     public Account registerAccount(String username, String password) {
+        if (username == null || username.trim().isEmpty() || username.trim().length() < 3) {
+            throw new RuntimeException("Username must be at least 3 characters");
+        }
+        username = username.trim();
+        if (password == null || password.length() < 8) {
+            throw new RuntimeException("Password must be at least 8 characters");
+        }
         if (accountRepository.findByUsername(username).isPresent()) {
-            throw new RuntimeException("Username already exists");
+            throw new RuntimeException("Registration failed. Please try a different username.");
         }
 
         Account account = new Account();
         account.setUsername(username);
-        account.setPassword(passwordEncoder.encode(password)); // Encrypt password
-        account.setBalance(BigDecimal.ZERO); // Initial balance set to 0
+        account.setPassword(passwordEncoder.encode(password));
+        account.setBalance(BigDecimal.ZERO);
         return accountRepository.save(account);
     }
 
 
+    @Transactional
     public void deposit(Account account, BigDecimal amount) {
+        if (amount == null || amount.compareTo(BigDecimal.ZERO) <= 0) {
+            throw new RuntimeException("Amount must be positive");
+        }
         account.setBalance(account.getBalance().add(amount));
         accountRepository.save(account);
 
@@ -61,7 +73,11 @@ public void deposit(Account account, BigDecimal amount) {
         transactionRepository.save(transaction);
     }
 
+    @Transactional
     public void withdraw(Account account, BigDecimal amount) {
+        if (amount == null || amount.compareTo(BigDecimal.ZERO) <= 0) {
+            throw new RuntimeException("Amount must be positive");
+        }
         if (account.getBalance().compareTo(amount) < 0) {
             throw new RuntimeException("Insufficient funds");
         }
@@ -100,7 +116,11 @@ public Collection<? extends GrantedAuthority> authorities() {
         return Arrays.asList(new SimpleGrantedAuthority("USER"));
     }
 
+    @Transactional
     public void transferAmount(Account fromAccount, String toUsername, BigDecimal amount) {
+        if (amount == null || amount.compareTo(BigDecimal.ZERO) <= 0) {
+            throw new RuntimeException("Amount must be positive");
+        }
         if (fromAccount.getBalance().compareTo(amount) < 0) {
             throw new RuntimeException("Insufficient funds");
         }
diff --git a/src/main/resources/templates/dashboard.html b/src/main/resources/templates/dashboard.html
index 23a0cc7f..d039ab61 100644
--- a/src/main/resources/templates/dashboard.html
+++ b/src/main/resources/templates/dashboard.html
@@ -117,7 +117,11 @@
     <ul class="navbar-nav ml-auto">
         <li class="nav-item"><a class="nav-link" href="/dashboard">Dashboard</a></li>
         <li class="nav-item"><a class="nav-link" href="/transactions">Transactions</a></li>
-        <li class="nav-item"><a class="nav-link" href="/logout">Logout</a></li>
+        <li class="nav-item">
+            <form method="post" th:action="@{/logout}" style="display:inline;">
+                <button type="submit" class="nav-link btn btn-link" style="color:#ffffff !important;cursor:pointer;">Logout</button>
+            </form>
+        </li>
     </ul>
 </nav>
 
@@ -141,7 +145,7 @@ <h4>Account Details</h4>
                 Deposit
             </button>
             <div class="collapse mt-3" id="depositForm">
-                <form method="post" action="/deposit" class="form-container">
+                <form method="post" th:action="@{/deposit}" class="form-container">
                     <div class="form-group">
                         <label>Amount:</label>
                         <input type="number" class="form-control" name="amount" required />
@@ -157,7 +161,7 @@ <h4>Account Details</h4>
                 Withdraw
             </button>
             <div class="collapse mt-3" id="withdrawForm">
-                <form method="post" action="/withdraw" class="form-container">
+                <form method="post" th:action="@{/withdraw}" class="form-container">
                     <div class="form-group">
                         <label>Amount:</label>
                         <input type="number" class="form-control" name="amount" required />
@@ -173,7 +177,7 @@ <h4>Account Details</h4>
                 Transfer Money
             </button>
             <div class="collapse mt-3" id="transferForm">
-                <form method="post" action="/transfer" class="form-container">
+                <form method="post" th:action="@{/transfer}" class="form-container">
                     <div class="form-group">
                         <label>Recipient Username:</label>
                         <input type="text" class="form-control" name="toUsername" required />
diff --git a/src/main/resources/templates/login.html b/src/main/resources/templates/login.html
index 7b40190d..412a68eb 100644
--- a/src/main/resources/templates/login.html
+++ b/src/main/resources/templates/login.html
@@ -105,7 +105,7 @@
 
 <div class="container">
     <h2 class="text-left">Login</h2>
-    <form method="post" action="/login">
+    <form method="post" th:action="@{/login}">
         <div class="form-group">
             <label>Username:</label>
             <input type="text" class="form-control" name="username" required />
diff --git a/src/main/resources/templates/register.html b/src/main/resources/templates/register.html
index e410b74e..b5041caf 100644
--- a/src/main/resources/templates/register.html
+++ b/src/main/resources/templates/register.html
@@ -105,7 +105,7 @@
 
 <div class="container">
     <h2 class="text-left">Register a New Account</h2>
-    <form method="post" action="/register">
+    <form method="post" th:action="@{/register}">
         <div class="form-group">
             <label>Username:</label>
             <input type="text" class="form-control" name="username" required />
@@ -119,7 +119,7 @@ <h2 class="text-left">Register a New Account</h2>
     <p class="mt-3">Already have an account? <a href="/login" class="custom-link">Login here</a></p>
 
     <div th:if="${error}" class="alert alert-danger mt-3 text-center">
-        User already present.
+        <span th:text="${error}"></span>
     </div>
 </div>
 
diff --git a/src/main/resources/templates/transactions.html b/src/main/resources/templates/transactions.html
index 307bc5de..e6291b3f 100644
--- a/src/main/resources/templates/transactions.html
+++ b/src/main/resources/templates/transactions.html
@@ -96,7 +96,11 @@
     <ul class="navbar-nav ml-auto">
         <li class="nav-item"><a class="nav-link" href="/dashboard">Dashboard</a></li>
         <li class="nav-item"><a class="nav-link" href="/transactions">Transactions</a></li>
-        <li class="nav-item"><a class="nav-link" href="/logout">Logout</a></li>
+        <li class="nav-item">
+            <form method="post" th:action="@{/logout}" style="display:inline;">
+                <button type="submit" class="nav-link btn btn-link" style="color:#ffffff !important;cursor:pointer;">Logout</button>
+            </form>
+        </li>
     </ul>
 </nav>
 
diff --git a/src/test/resources/application.properties b/src/test/resources/application.properties
new file mode 100644
index 00000000..550f3d4d
--- /dev/null
+++ b/src/test/resources/application.properties
@@ -0,0 +1,6 @@
+spring.datasource.url=jdbc:h2:mem:testdb;DB_CLOSE_DELAY=-1
+spring.datasource.driver-class-name=org.h2.Driver
+spring.datasource.username=sa
+spring.datasource.password=
+spring.jpa.hibernate.ddl-auto=create-drop
+spring.jpa.show-sql=true