fix: deprecate non-functional NexusClassSource MAVEN mode

- Add @deprecated annotation to MAVEN mode enum value
- Replace broken loadFromMaven() with UnsupportedOperationException
- Document searchInJars() is completely non-functional
- Update README to note MAVEN mode is deprecated
- Direct users to use MavenNexusClassSource instead

searchInJars() has backwards logic (returns null on success), swallows
all exceptions, and never actually searches JAR files. Fixing it would
require full JSON parsing of Nexus Search API - significant work.

MavenNexusClassSource already provides complete, working implementation.

Fixes #57

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: Flossy

README.md

@@ -138,6 +138,8 @@ JClassLoader authLoader = JClassLoader.builder()
 
 #### Loading from Nexus Maven Repository
 
+**Note:** Use `MavenNexusClassSource` for loading classes from Maven artifacts in Nexus. The `NexusClassSource` MAVEN mode is deprecated and non-functional.
+
 Load classes from JAR files stored as Maven artifacts:
 
 ```java

src/main/java/org/flossware/classloader/NexusClassSource.java

@@ -32,11 +32,19 @@ public class NexusClassSource implements ClassSource {
 
     /**
      * Nexus repository mode.
+     *
+     * <p><b>WARNING:</b> MAVEN mode is currently non-functional due to incomplete
+     * implementation of searchInJars(). Use MavenNexusClassSource instead for loading
+     * classes from Maven artifacts in Nexus, or use RAW mode for direct .class files.</p>
      */
     public enum NexusMode {
         /** Raw repository with direct .class files */
         RAW,
-        /** Maven repository with JAR files */
+        /**
+         * Maven repository with JAR files.
+         * @deprecated MAVEN mode is non-functional. Use {@link MavenNexusClassSource} instead.
+         */
+        @Deprecated
         MAVEN
     }
 
@@ -109,48 +117,41 @@ private byte[] loadFromRaw(String className) throws IOException {
         return fetchUrl(url);
     }
 
+    /**
+     * @deprecated MAVEN mode is non-functional. searchInJars() is broken.
+     *             Use {@link MavenNexusClassSource} instead.
+     */
+    @Deprecated
     private byte[] loadFromMaven(String className) throws IOException {
-        String packagePath = getPackagePath(className);
-        if (packagePath == null) {
-            throw new IOException("Cannot determine Maven coordinates for class: " + className);
-        }
-
-        String cachedKey = packagePath;
-        // Atomic get() - avoids TOCTOU race condition with contains() + get()
-        byte[] cachedData = jarCache.get(cachedKey);
-        if (cachedData != null) {
-            return cachedData;
-        }
-
-        String simpleClassName = getSimpleClassName(className);
-        String classFileInJar = ClassNameUtil.toClassFilePath(className);
-
-        byte[] classData = searchInJars(packagePath, classFileInJar);
-        if (classData != null) {
-            jarCache.put(cachedKey, classData);
-            return classData;
-        }
-
-        throw new IOException("Class not found in Nexus Maven repository: " + className);
+        throw new UnsupportedOperationException(
+            "MAVEN mode is non-functional (searchInJars() not implemented). " +
+            "Use MavenNexusClassSource instead for loading classes from Maven artifacts in Nexus."
+        );
     }
 
+    /**
+     * @deprecated This method is non-functional (returns null always).
+     *             Proper implementation would require JSON parsing of Nexus search API response.
+     */
+    @Deprecated
+    @SuppressWarnings("unused")
     private byte[] searchInJars(String packagePath, String classFileInJar) throws IOException {
-        String searchUrl = nexusUrl + "service/rest/v1/search?repository=" + repository + "&name=" + packagePath;
-
-        try {
-            URL url = new URL(searchUrl);
-            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
-            configureAuthentication(connection);
-            connection.setRequestMethod("GET");
-
-            int responseCode = connection.getResponseCode();
-            if (responseCode == HttpURLConnection.HTTP_OK) {
-                return null;
-            }
-        } catch (IOException e) {
-        }
-
-        return null;
+        // This method is completely broken:
+        // 1. Returns null when HTTP 200 OK (backwards logic!)
+        // 2. Swallows all exceptions
+        // 3. Never actually parses the response or downloads JARs
+        // 4. Always returns null
+        //
+        // Proper implementation would require:
+        // - Parse Nexus search API JSON response
+        // - Extract JAR download URLs
+        // - Download each JAR and search for the class
+        // - Return class bytecode
+        //
+        // Use MavenNexusClassSource instead - it's a complete implementation.
+        throw new UnsupportedOperationException(
+            "searchInJars() is not implemented. Use MavenNexusClassSource instead."
+        );
     }
 
     private byte[] fetchUrl(String urlString) throws IOException {