fix: resolve nullability issues identified by NullAway

Author: Tyreviel

src/main/java/org/juv25d/FilterRegistration.java

@@ -1,8 +1,9 @@
 package org.juv25d;
 
+import org.jspecify.annotations.Nullable;
 import org.juv25d.filter.Filter;
 
-public record FilterRegistration(Filter filter, int order, String pattern)
+public record FilterRegistration(Filter filter, int order, @Nullable String pattern)
     implements Comparable<FilterRegistration> {
 
     @Override

src/main/java/org/juv25d/Pipeline.java

@@ -4,6 +4,7 @@
 import org.juv25d.filter.FilterChainImpl;
 import org.juv25d.http.HttpRequest;
 import org.juv25d.router.Router; // New import
+import org.juv25d.router.SimpleRouter;
 
 import java.util.ArrayList;
 import java.util.Collections;
@@ -18,7 +19,7 @@ public class Pipeline {
     private final List<FilterRegistration> globalFilters = new CopyOnWriteArrayList<>();
     private final Map<String, List<FilterRegistration>> routeFilters = new ConcurrentHashMap<>();
     private volatile List<Filter> sortedGlobalFilters = List.of();
-    private volatile Router router; // Changed from Plugin plugin;
+    private volatile Router router = new SimpleRouter(); // Changed from Plugin plugin;
 
     public void addGlobalFilter(Filter filter, int order) {
         globalFilters.add(new FilterRegistration(filter, order, null));

src/main/java/org/juv25d/http/HttpParser.java

@@ -4,6 +4,7 @@
 import java.io.InputStream;
 import java.util.Map;
 import java.util.TreeMap;
+import org.jspecify.annotations.Nullable;
 
 public class HttpParser {
 
@@ -63,6 +64,7 @@ public HttpRequest parse(InputStream in) throws IOException {
         return new HttpRequest(method, path, query, version, headers, body, "UNKNOWN");
     }
 
+    @Nullable
     private String readLine(InputStream in) throws IOException {
         StringBuilder sb = new StringBuilder();
         int b;

src/main/java/org/juv25d/http/HttpRequest.java

@@ -1,11 +1,12 @@
 package org.juv25d.http;
 
 import java.util.Map;
+import org.jspecify.annotations.Nullable;
 
 public record HttpRequest(
         String method,
         String path,
-        String queryString,
+        @Nullable String queryString,
         String httpVersion,
         Map<String, String> headers,
         byte[] body,

src/main/java/org/juv25d/http/HttpResponse.java

@@ -15,6 +15,8 @@ public class HttpResponse {
     private byte[] body;
 
     public HttpResponse(){
+        this.statusCode = 200;
+        this.statusText = "OK";
         this.headers = new LinkedHashMap<>();
         this.body = new byte[0];
     }

src/main/java/org/juv25d/util/ConfigLoader.java

@@ -1,15 +1,17 @@
 package org.juv25d.util;
 
+import org.jspecify.annotations.Nullable;
 import org.yaml.snakeyaml.Yaml;
 
 import java.io.InputStream;
 import java.util.Map;
 
 public class ConfigLoader {
+    @Nullable
     private static ConfigLoader instance;
     private int port;
-    private String logLevel;
-    private String rootDirectory;
+    private String logLevel = "INFO";
+    private String rootDirectory = "static";
     private long requestsPerMinute;
     private long burstCapacity;
     private boolean rateLimitingEnabled;
@@ -45,7 +47,7 @@ private void loadConfiguration() {
             // logging
             Map<String, Object> loggingConfig = (Map<String, Object>) config.get("logging");
             if (loggingConfig != null) {
-                this.logLevel = (String) loggingConfig.get("level");
+                this.logLevel = (String) loggingConfig.getOrDefault("level", "INFO");
             }
 
             // rate-limiting