Add logging improvements, shutdown listener, and request filter

- Introduced `ShutdownListener` to log application shutdown details and thread stack dump.
- Added `RequestLoggerFilter` to log incoming HTTP requests and responses.
- Enhanced `LccApplication` with memory usage logging at start and end.
- Replaced `System.out` calls with SLF4J logging in `DevUserEmulationFilter`.
- Updated `pom.xml` to mark devtools dependency as optional.

pom.xml

@@ -33,11 +33,6 @@
         <flyway.version>11.18.0</flyway.version>
     </properties>
     <dependencies>
-
-        <dependency>
-            <groupId>org.springframework.boot</groupId>
-            <artifactId>spring-boot-starter-batch</artifactId>
-        </dependency>
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-jdbc</artifactId>
@@ -139,6 +134,7 @@
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-devtools</artifactId>
             <scope>runtime</scope>
+            <optional>true</optional>
         </dependency>
         <dependency>
             <groupId>org.mockito</groupId>

src/main/java/de/avatic/lcc/LccApplication.java

@@ -1,13 +1,26 @@
 package de.avatic.lcc;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 
 @SpringBootApplication
 public class LccApplication {
 
-	public static void main(String[] args) {
-		SpringApplication.run(LccApplication.class, args);
-	}
+    static Logger logger = LoggerFactory.getLogger(LccApplication.class);
+
+    public static void main(String[] args) {
+
+        Runtime runtime = Runtime.getRuntime();
+        long usedMemory = (runtime.totalMemory() - runtime.freeMemory()) / 1024 / 1024;
+        logger.info("LCC Start - Memory: {} used, {} total, {} free, {} max ", usedMemory, runtime.totalMemory() / 1024 / 1024, runtime.freeMemory() / 1024 / 1024, runtime.maxMemory() / 1024 / 1024);
+
+        SpringApplication.run(LccApplication.class, args);
+
+        usedMemory = (runtime.totalMemory() - runtime.freeMemory()) / 1024 / 1024;
+        logger.info("LCC End - Memory: {} used, {} total, {} free, {} max ", usedMemory, runtime.totalMemory() / 1024 / 1024, runtime.freeMemory() / 1024 / 1024, runtime.maxMemory() / 1024 / 1024);
+
+    }
 
 }

src/main/java/de/avatic/lcc/config/ShutdownListener.java

@@ -0,0 +1,20 @@
+package de.avatic.lcc.config;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.context.event.ContextClosedEvent;
+import org.springframework.context.event.EventListener;
+import org.springframework.stereotype.Component;
+
+@Component
+public class ShutdownListener {
+
+    private static final Logger log = LoggerFactory.getLogger(ShutdownListener.class);
+
+    @EventListener
+    public void onShutdown(ContextClosedEvent event) {
+        log.error("Application shutdown. Context: {}, Thread: {}", event.getApplicationContext(), Thread.currentThread().getName());
+        log.error("Thread stack dump:");
+        Thread.dumpStack();
+    }
+}

src/main/java/de/avatic/lcc/config/filter/DevUserEmulationFilter.java

@@ -10,6 +10,8 @@ import jakarta.servlet.http.HttpServletRequest;
 import jakarta.servlet.http.HttpServletResponse;
 import jakarta.servlet.http.HttpSession;
 import org.jetbrains.annotations.NotNull;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import org.springframework.context.annotation.Profile;
 import org.springframework.security.core.Authentication;
 import org.springframework.security.core.GrantedAuthority;
@@ -32,6 +34,8 @@ import java.util.Set;
 @Profile("dev | test")
 public class DevUserEmulationFilter extends OncePerRequestFilter {
 
+    private final Logger log = LoggerFactory.getLogger(DevUserEmulationFilter.class);
+
     private static final String DEV_USER_ID_SESSION_KEY = "dev.emulated.user.id";
     private final UserRepository userRepository;
 
@@ -48,17 +52,17 @@ public class DevUserEmulationFilter extends OncePerRequestFilter {
         Integer emulatedUserId = (Integer) session.getAttribute(DEV_USER_ID_SESSION_KEY);
 
         // Add logging to debug
-        System.out.println("DevUserEmulationFilter - Session ID: " + session.getId());
-        System.out.println("DevUserEmulationFilter - Emulated User ID: " + emulatedUserId);
+        log.debug("DevUserEmulationFilter - Session ID: " + session.getId());
+        log.debug("DevUserEmulationFilter - Emulated User ID: " + emulatedUserId);
 
         if(emulatedUserId != null) {
             User user = userRepository.getById(emulatedUserId);
             if (user != null) {
                 setEmulatedUser(user);
-                System.out.println("DevUserEmulationFilter - Set user: " + user.getEmail());
+                log.debug("DevUserEmulationFilter - Set user: " + user.getEmail());
             }
         } else {
-            System.out.println("DevUserEmulationFilter - " + request.getRequestURI() + " - No emulated user set");
+            log.debug("DevUserEmulationFilter - " + request.getRequestURI() + " - No emulated user set");
         }
 
         filterChain.doFilter(request, response);

src/main/java/de/avatic/lcc/config/filter/RequestLoggerFilter.java

@@ -0,0 +1,54 @@
+package de.avatic.lcc.config.filter;
+
+import jakarta.servlet.*;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Component;
+
+import java.io.IOException;
+
+@Component
+public class RequestLoggerFilter implements Filter {
+
+    private static final Logger log = LoggerFactory.getLogger(RequestLoggerFilter.class);
+
+    @Override
+    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
+            throws IOException, ServletException {
+
+        HttpServletRequest httpRequest = (HttpServletRequest) request;
+        HttpServletResponse httpResponse = (HttpServletResponse) response;
+
+        long startTime = System.currentTimeMillis();
+
+        log.info(">>> INCOMING REQUEST: {} {} from {} - Headers: {}",
+                httpRequest.getMethod(),
+                httpRequest.getRequestURI(),
+                httpRequest.getRemoteAddr(),
+                getHeadersAsString(httpRequest));
+
+        try {
+            chain.doFilter(request, response);
+        } finally {
+            long duration = System.currentTimeMillis() - startTime;
+            log.info("<<< RESPONSE: {} {} -> Status: {} ({}ms)",
+                    httpRequest.getMethod(),
+                    httpRequest.getRequestURI(),
+                    httpResponse.getStatus(),
+                    duration);
+        }
+    }
+
+    private String getHeadersAsString(HttpServletRequest request) {
+        StringBuilder headers = new StringBuilder();
+        var headerNames = request.getHeaderNames();
+        while (headerNames.hasMoreElements()) {
+            String headerName = headerNames.nextElement();
+            headers.append(headerName).append("=")
+                    .append(request.getHeader(headerName)).append("; ");
+        }
+        return headers.toString();
+    }
+}