diff --git a/src/main/java/robaho/net/httpserver/AuthFilter.java b/src/main/java/robaho/net/httpserver/AuthFilter.java
index 9e40d4f..9c5a48a 100644
--- a/src/main/java/robaho/net/httpserver/AuthFilter.java
+++ b/src/main/java/robaho/net/httpserver/AuthFilter.java
@@ -29,7 +29,7 @@
 
 import java.io.*;
 
-public class AuthFilter extends Filter {
+public final class AuthFilter extends Filter {
 
     private Authenticator authenticator;
 
@@ -37,6 +37,7 @@ public AuthFilter(Authenticator authenticator) {
         this.authenticator = authenticator;
     }
 
+    @Override
     public String description() {
         return "Authentication filter";
     }
@@ -56,6 +57,7 @@ public void consumeInput(HttpExchange t) throws IOException {
     /**
      * The filter's implementation, which is invoked by the server
      */
+    @Override
     public void doFilter(HttpExchange t, Filter.Chain chain) throws IOException {
         if (authenticator != null) {
             Authenticator.Result r = authenticator.authenticate(t);
diff --git a/src/main/java/robaho/net/httpserver/Code.java b/src/main/java/robaho/net/httpserver/Code.java
index a32a5cc..edb842e 100644
--- a/src/main/java/robaho/net/httpserver/Code.java
+++ b/src/main/java/robaho/net/httpserver/Code.java
@@ -25,7 +25,7 @@
 
 package robaho.net.httpserver;
 
-public class Code {
+public final class Code {
 
   public static final int HTTP_CONTINUE = 100;
   public static final int HTTP_OK = 200;
diff --git a/src/main/java/robaho/net/httpserver/ContextList.java b/src/main/java/robaho/net/httpserver/ContextList.java
index 494724c..ec0ef68 100644
--- a/src/main/java/robaho/net/httpserver/ContextList.java
+++ b/src/main/java/robaho/net/httpserver/ContextList.java
@@ -29,13 +29,13 @@
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.CopyOnWriteArrayList;
 
-class ContextList {
+final class ContextList {
 
     private final List<HttpContextImpl> list = new CopyOnWriteArrayList<>();
     private final Map<CacheKey,HttpContextImpl> cache = new ConcurrentHashMap<>();
     private record CacheKey(String protocol,String path){}
 
-    public synchronized void add(HttpContextImpl ctx) {
+    synchronized void add(HttpContextImpl ctx) {
         assert ctx.getPath() != null;
         if (contains(ctx)) {
             throw new IllegalArgumentException("cannot add context to list");
@@ -47,7 +47,7 @@ boolean contains(HttpContextImpl ctx) {
         return findContext(ctx.getProtocol(), ctx.getPath(), true) != null;
     }
 
-    public int size() {
+    int size() {
         return list.size();
     }
 
@@ -90,7 +90,7 @@ HttpContextImpl findContext(String protocol, String path, boolean exact) {
         return lc;
     }
 
-    public synchronized void remove(String protocol, String path)
+    synchronized void remove(String protocol, String path)
             throws IllegalArgumentException {
         HttpContextImpl ctx = findContext(protocol, path, true);
         if (ctx == null) {
@@ -99,7 +99,7 @@ public synchronized void remove(String protocol, String path)
         list.remove(ctx);
     }
 
-    public synchronized void remove(HttpContextImpl context)
+    synchronized void remove(HttpContextImpl context)
             throws IllegalArgumentException {
         for (HttpContextImpl ctx : list) {
             if (ctx.equals(context)) {
diff --git a/src/main/java/robaho/net/httpserver/DefaultHttpServerProvider.java b/src/main/java/robaho/net/httpserver/DefaultHttpServerProvider.java
index 6fd1feb..4c0de2b 100644
--- a/src/main/java/robaho/net/httpserver/DefaultHttpServerProvider.java
+++ b/src/main/java/robaho/net/httpserver/DefaultHttpServerProvider.java
@@ -30,11 +30,14 @@
 import com.sun.net.httpserver.*;
 import com.sun.net.httpserver.spi.*;
 
-public class DefaultHttpServerProvider extends HttpServerProvider {
+public final class DefaultHttpServerProvider extends HttpServerProvider {
+
+    @Override
     public HttpServer createHttpServer(InetSocketAddress addr, int backlog) throws IOException {
         return new HttpServerImpl(addr, backlog);
     }
 
+    @Override
     public HttpsServer createHttpsServer(InetSocketAddress addr, int backlog) throws IOException {
         return new HttpsServerImpl(addr, backlog);
     }
diff --git a/src/main/java/robaho/net/httpserver/DelegatingHttpExchange.java b/src/main/java/robaho/net/httpserver/DelegatingHttpExchange.java
index b36ed2b..6d554c9 100644
--- a/src/main/java/robaho/net/httpserver/DelegatingHttpExchange.java
+++ b/src/main/java/robaho/net/httpserver/DelegatingHttpExchange.java
@@ -44,64 +44,81 @@ public DelegatingHttpExchange(HttpExchange ex) {
         this.exchange = ex;
     }
 
+    @Override
     public abstract Headers getRequestHeaders();
 
+    @Override
     public abstract String getRequestMethod();
 
+    @Override
     public abstract URI getRequestURI();
 
+    @Override
     public Headers getResponseHeaders() {
         return exchange.getResponseHeaders();
     }
 
+    @Override
     public HttpContext getHttpContext() {
         return exchange.getHttpContext();
     }
 
+    @Override
     public void close() {
         exchange.close();
     }
 
+    @Override
     public InputStream getRequestBody() {
         return exchange.getRequestBody();
     }
 
+    @Override
     public int getResponseCode() {
         return exchange.getResponseCode();
     }
 
+    @Override
     public OutputStream getResponseBody() {
         return exchange.getResponseBody();
     }
 
+    @Override
     public void sendResponseHeaders(int rCode, long contentLen) throws IOException {
         exchange.sendResponseHeaders(rCode, contentLen);
     }
 
+    @Override
     public InetSocketAddress getRemoteAddress() {
         return exchange.getRemoteAddress();
     }
 
+    @Override
     public InetSocketAddress getLocalAddress() {
         return exchange.getLocalAddress();
     }
 
+    @Override
     public String getProtocol() {
         return exchange.getProtocol();
     }
 
+    @Override
     public Object getAttribute(String name) {
         return exchange.getAttribute(name);
     }
 
+    @Override
     public void setAttribute(String name, Object value) {
         exchange.setAttribute(name, value);
     }
 
+    @Override
     public void setStreams(InputStream i, OutputStream o) {
         exchange.setStreams(i, o);
     }
 
+    @Override
     public HttpPrincipal getPrincipal() {
         return exchange.getPrincipal();
     }
diff --git a/src/main/java/robaho/net/httpserver/ExchangeImpl.java b/src/main/java/robaho/net/httpserver/ExchangeImpl.java
index 956838b..6385646 100644
--- a/src/main/java/robaho/net/httpserver/ExchangeImpl.java
+++ b/src/main/java/robaho/net/httpserver/ExchangeImpl.java
@@ -42,7 +42,7 @@
 
 import robaho.net.httpserver.websockets.WebSocketHandler;
 
-class ExchangeImpl {
+final class ExchangeImpl {
 
     Headers reqHdrs, rspHdrs;
     Request req;
@@ -108,23 +108,23 @@ class ExchangeImpl {
         this.ris = req.inputStream();
     }
 
-    public Headers getRequestHeaders() {
+    Headers getRequestHeaders() {
         return reqHdrs;
     }
 
-    public Headers getResponseHeaders() {
+    Headers getResponseHeaders() {
         return rspHdrs;
     }
 
-    public URI getRequestURI() {
+    URI getRequestURI() {
         return uri;
     }
 
-    public String getRequestMethod() {
+    String getRequestMethod() {
         return method;
     }
 
-    public HttpContextImpl getHttpContext() {
+    HttpContextImpl getHttpContext() {
         return connection.getHttpContext();
     }
 
@@ -136,7 +136,7 @@ private boolean isConnectRequest() {
         return CONNECT.equals(getRequestMethod());
     }
 
-    public void close() {
+    void close() {
         if (closed) {
             return;
         }
@@ -166,7 +166,7 @@ public void close() {
         }
     }
 
-    public InputStream getRequestBody() {
+    InputStream getRequestBody() {
         if (uis != null) {
             return uis;
         }
@@ -187,11 +187,11 @@ LeftOverInputStream getOriginalInputStream() {
         return uis_orig;
     }
 
-    public int getResponseCode() {
+    int getResponseCode() {
         return rcode;
     }
 
-    public OutputStream getResponseBody() {
+    OutputStream getResponseBody() {
         /*
          * TODO. Change spec to remove restriction below. Filters
          * cannot work with this restriction
@@ -219,7 +219,7 @@ PlaceholderOutputStream getPlaceholderResponseBody() {
 
     // hard-coded formatting for Date header, rather than using slower DateFormatter
     
-    public void sendResponseHeaders(int rCode, long contentLen)
+    void sendResponseHeaders(int rCode, long contentLen)
             throws IOException {
         final Logger logger = getServerImpl().getLogger();
         if (sentHeaders) {
@@ -353,31 +353,31 @@ void writeHeaders(Headers map, OutputStream os) throws IOException {
         outputAscii(CRNL,os);
     }
 
-    public InetSocketAddress getRemoteAddress() {
+    InetSocketAddress getRemoteAddress() {
         Socket s = connection.getSocket();
         InetAddress ia = s.getInetAddress();
         int port = s.getPort();
         return new InetSocketAddress(ia, port);
     }
 
-    public InetSocketAddress getLocalAddress() {
+    InetSocketAddress getLocalAddress() {
         Socket s = connection.getSocket();
         InetAddress ia = s.getLocalAddress();
         int port = s.getLocalPort();
         return new InetSocketAddress(ia, port);
     }
 
-    public String getProtocol() {
+    String getProtocol() {
         String reqline = req.requestLine();
         int index = reqline.lastIndexOf(" ");
         return reqline.substring(index + 1);
     }
 
-    public SSLSession getSSLSession() {
+    SSLSession getSSLSession() {
         return connection.getSSLSession();
     }
 
-    public Object getAttribute(String name) {
+    Object getAttribute(String name) {
         if (name == null) {
             throw new NullPointerException("null name parameter");
         }
@@ -387,7 +387,7 @@ public Object getAttribute(String name) {
         return attributes.get(name);
     }
 
-    public void setAttribute(String name, Object value) {
+    void setAttribute(String name, Object value) {
         if (name == null) {
             throw new NullPointerException("null name parameter");
         }
@@ -401,7 +401,7 @@ public void setAttribute(String name, Object value) {
         }
     }
 
-    public void setStreams(InputStream i, OutputStream o) {
+    void setStreams(InputStream i, OutputStream o) {
         assert uis != null;
         if (i != null) {
             uis = i;
@@ -422,7 +422,7 @@ ServerImpl getServerImpl() {
         return getHttpContext().getServerImpl();
     }
 
-    public HttpPrincipal getPrincipal() {
+    HttpPrincipal getPrincipal() {
         return principal;
     }
 
@@ -447,7 +447,7 @@ static ExchangeImpl get(HttpExchange t) {
  * the wrapped stream has been provided, then an IOException will
  * be thrown.
  */
-class PlaceholderOutputStream extends java.io.OutputStream {
+final class PlaceholderOutputStream extends java.io.OutputStream {
 
     OutputStream wrapped;
 
@@ -469,26 +469,31 @@ private void checkWrap() throws IOException {
         }
     }
 
+    @Override
     public void write(int b) throws IOException {
         checkWrap();
         wrapped.write(b);
     }
 
+    @Override
     public void write(byte b[]) throws IOException {
         checkWrap();
         wrapped.write(b);
     }
 
+    @Override
     public void write(byte b[], int off, int len) throws IOException {
         checkWrap();
         wrapped.write(b, off, len);
     }
 
+    @Override
     public void flush() throws IOException {
         checkWrap();
         wrapped.flush();
     }
 
+    @Override
     public void close() throws IOException {
         checkWrap();
         wrapped.close();
diff --git a/src/main/java/robaho/net/httpserver/FixedLengthInputStream.java b/src/main/java/robaho/net/httpserver/FixedLengthInputStream.java
index d3f22ea..b263da9 100644
--- a/src/main/java/robaho/net/httpserver/FixedLengthInputStream.java
+++ b/src/main/java/robaho/net/httpserver/FixedLengthInputStream.java
@@ -33,7 +33,7 @@
  * close() does not close the underlying stream
  */
 
-class FixedLengthInputStream extends LeftOverInputStream {
+final class FixedLengthInputStream extends LeftOverInputStream {
     private long remaining;
 
     FixedLengthInputStream(ExchangeImpl t, InputStream src, long len) {
@@ -44,6 +44,7 @@ class FixedLengthInputStream extends LeftOverInputStream {
         this.remaining = len;
     }
 
+    @Override
     protected int readImpl(byte[] b, int off, int len) throws IOException {
 
         eof = (remaining == 0L);
@@ -62,6 +63,7 @@ protected int readImpl(byte[] b, int off, int len) throws IOException {
         return n;
     }
 
+    @Override
     public int available() throws IOException {
         if (eof) {
             return 0;
@@ -70,13 +72,16 @@ public int available() throws IOException {
         return n < remaining ? n : (int) remaining;
     }
 
+    @Override
     public boolean markSupported() {
         return false;
     }
 
+    @Override
     public void mark(int l) {
     }
 
+    @Override
     public void reset() throws IOException {
         throw new IOException("mark/reset not supported");
     }
diff --git a/src/main/java/robaho/net/httpserver/FixedLengthOutputStream.java b/src/main/java/robaho/net/httpserver/FixedLengthOutputStream.java
index 85c00b3..5f2663b 100644
--- a/src/main/java/robaho/net/httpserver/FixedLengthOutputStream.java
+++ b/src/main/java/robaho/net/httpserver/FixedLengthOutputStream.java
@@ -36,10 +36,10 @@
  * normal close() does not close the underlying stream
  */
 
-class FixedLengthOutputStream extends FilterOutputStream {
+final class FixedLengthOutputStream extends FilterOutputStream {
     private long remaining;
     private boolean closed = false;
-    ExchangeImpl t;
+    private final ExchangeImpl t;
 
     FixedLengthOutputStream(ExchangeImpl t, OutputStream src, long len) {
         super(src);
@@ -50,6 +50,7 @@ class FixedLengthOutputStream extends FilterOutputStream {
         this.remaining = len;
     }
 
+    @Override
     public void write(int b) throws IOException {
         if (closed) {
             throw new IOException("stream closed");
@@ -61,6 +62,7 @@ public void write(int b) throws IOException {
         remaining--;
     }
 
+    @Override
     public void write(byte[] b, int off, int len) throws IOException {
         Objects.checkFromIndexSize(off, len, b.length);
         if (len == 0) {
@@ -77,6 +79,7 @@ public void write(byte[] b, int off, int len) throws IOException {
         remaining -= len;
     }
 
+    @Override
     public void close() throws IOException {
         if (closed) {
             return;
diff --git a/src/main/java/robaho/net/httpserver/HttpConnection.java b/src/main/java/robaho/net/httpserver/HttpConnection.java
index 4375a8a..9edaf07 100644
--- a/src/main/java/robaho/net/httpserver/HttpConnection.java
+++ b/src/main/java/robaho/net/httpserver/HttpConnection.java
@@ -42,14 +42,14 @@
  * one of these is hung from the selector attachment and is used to locate
  * everything from that.
  */
-class HttpConnection {
+final class HttpConnection {
     private static final Logger logger = System.getLogger("robaho.net.httpserver");
 
     HttpContextImpl context;
 
     /* low level stream that sits directly over channel */
-    InputStream is;
-    OutputStream os;
+    final InputStream is;
+    final OutputStream os;
 
     final Socket socket;
     volatile boolean closed = false;
@@ -139,7 +139,7 @@ HttpContextImpl getHttpContext() {
         return context;
     }
 
-    private class ActivityTimerInputStream extends FilterInputStream {
+    private final class ActivityTimerInputStream extends FilterInputStream {
 
         private ActivityTimerInputStream(InputStream inputStream) {
             super(inputStream);
@@ -175,7 +175,7 @@ public int read(byte b[], int off, int len) throws IOException {
 
     }
 
-    private class ActivityTimerOutputStream extends FilterOutputStream {
+    private final class ActivityTimerOutputStream extends FilterOutputStream {
 
         private ActivityTimerOutputStream(OutputStream outputStream) {
             super(outputStream);
diff --git a/src/main/java/robaho/net/httpserver/HttpContextImpl.java b/src/main/java/robaho/net/httpserver/HttpContextImpl.java
index 013d6dc..2a85b32 100644
--- a/src/main/java/robaho/net/httpserver/HttpContextImpl.java
+++ b/src/main/java/robaho/net/httpserver/HttpContextImpl.java
@@ -41,7 +41,7 @@
  * {@link HttpServer#createContext(String,String,HttpHandler,Object)}
  * <p>
  */
-class HttpContextImpl extends HttpContext {
+final class HttpContextImpl extends HttpContext {
 
     private final String path;
     private final String protocol;
@@ -78,10 +78,12 @@ class HttpContextImpl extends HttpContext {
      * 
      * @return the HttpHandler for this context
      */
+    @Override
     public HttpHandler getHandler() {
         return handler;
     }
 
+    @Override
     public void setHandler(HttpHandler h) {
         if (h == null) {
             throw new NullPointerException("Null handler parameter");
@@ -97,6 +99,7 @@ public void setHandler(HttpHandler h) {
      * 
      * @return this context's path
      */
+    @Override
     public String getPath() {
         return path;
     }
@@ -106,6 +109,7 @@ public String getPath() {
      * 
      * @return this context's server
      */
+    @Override
     public HttpServer getServer() {
         return server.getWrapper();
     }
@@ -119,7 +123,7 @@ ServerImpl getServerImpl() {
      * 
      * @return this context's path
      */
-    public String getProtocol() {
+    String getProtocol() {
         return protocol;
     }
 
@@ -131,10 +135,12 @@ public String getProtocol() {
      * Every attribute stored in this Map will be visible to
      * every HttpExchange processed by this context
      */
+    @Override
     public Map<String, Object> getAttributes() {
         return attributes;
     }
 
+    @Override
     public List<Filter> getFilters() {
         return ufilters;
     }
@@ -143,6 +149,7 @@ List<Filter> getSystemFilters() {
         return sfilters;
     }
 
+    @Override
     public Authenticator setAuthenticator(Authenticator auth) {
         Authenticator old = authenticator;
         authenticator = auth;
@@ -150,6 +157,7 @@ public Authenticator setAuthenticator(Authenticator auth) {
         return old;
     }
 
+    @Override
     public Authenticator getAuthenticator() {
         return authenticator;
     }
diff --git a/src/main/java/robaho/net/httpserver/HttpExchangeImpl.java b/src/main/java/robaho/net/httpserver/HttpExchangeImpl.java
index c7e6138..de3b32f 100644
--- a/src/main/java/robaho/net/httpserver/HttpExchangeImpl.java
+++ b/src/main/java/robaho/net/httpserver/HttpExchangeImpl.java
@@ -29,79 +29,96 @@
 import java.net.*;
 import com.sun.net.httpserver.*;
 
-class HttpExchangeImpl extends HttpExchange {
+final class HttpExchangeImpl extends HttpExchange {
 
-    ExchangeImpl impl;
+    private final ExchangeImpl impl;
 
     HttpExchangeImpl(ExchangeImpl impl) {
         this.impl = impl;
     }
 
+    @Override
     public Headers getRequestHeaders() {
         return impl.getRequestHeaders();
     }
 
+    @Override
     public Headers getResponseHeaders() {
         return impl.getResponseHeaders();
     }
 
+    @Override
     public URI getRequestURI() {
         return impl.getRequestURI();
     }
 
+    @Override
     public String getRequestMethod() {
         return impl.getRequestMethod();
     }
 
+    @Override
     public HttpContextImpl getHttpContext() {
         return impl.getHttpContext();
     }
 
+    @Override
     public void close() {
         impl.close();
     }
 
+    @Override
     public InputStream getRequestBody() {
         return impl.getRequestBody();
     }
 
+    @Override
     public int getResponseCode() {
         return impl.getResponseCode();
     }
 
+    @Override
     public OutputStream getResponseBody() {
         return impl.getResponseBody();
     }
 
+    @Override
     public void sendResponseHeaders(int rCode, long contentLen)
             throws IOException {
         impl.sendResponseHeaders(rCode, contentLen);
     }
 
+    @Override
     public InetSocketAddress getRemoteAddress() {
         return impl.getRemoteAddress();
     }
 
+    @Override
     public InetSocketAddress getLocalAddress() {
         return impl.getLocalAddress();
     }
 
+    @Override
     public String getProtocol() {
         return impl.getProtocol();
     }
 
+    @Override
     public Object getAttribute(String name) {
         return impl.getAttribute(name);
     }
 
+    @Override
     public void setAttribute(String name, Object value) {
         impl.setAttribute(name, value);
     }
 
+    @Override
     public void setStreams(InputStream i, OutputStream o) {
         impl.setStreams(i, o);
     }
 
+    @Override
     public HttpPrincipal getPrincipal() {
         return impl.getPrincipal();
     }
diff --git a/src/main/java/robaho/net/httpserver/HttpServerImpl.java b/src/main/java/robaho/net/httpserver/HttpServerImpl.java
index 6f7843e..f1815ec 100644
--- a/src/main/java/robaho/net/httpserver/HttpServerImpl.java
+++ b/src/main/java/robaho/net/httpserver/HttpServerImpl.java
@@ -30,9 +30,9 @@
 import java.util.concurrent.*;
 import com.sun.net.httpserver.*;
 
-public class HttpServerImpl extends HttpServer {
+public final class HttpServerImpl extends HttpServer {
 
-    ServerImpl server;
+    private final ServerImpl server;
 
     HttpServerImpl() throws IOException {
         this(new InetSocketAddress(80), 0);
@@ -43,42 +43,52 @@ public class HttpServerImpl extends HttpServer {
         server = new ServerImpl(this, "http", addr, backlog);
     }
 
+    @Override
     public void bind(InetSocketAddress addr, int backlog) throws IOException {
         server.bind(addr, backlog);
     }
 
+    @Override
     public void start() {
         server.start();
     }
 
+    @Override
     public void setExecutor(Executor executor) {
         server.setExecutor(executor);
     }
 
+    @Override
     public Executor getExecutor() {
         return server.getExecutor();
     }
 
+    @Override
     public void stop(int delay) {
         server.stop(delay);
     }
 
-    public HttpContextImpl createContext(String path, HttpHandler handler) {
+    @Override
+    public HttpContext createContext(String path, HttpHandler handler) {
         return server.createContext(path, handler);
     }
 
-    public HttpContextImpl createContext(String path) {
+    @Override
+    public HttpContext createContext(String path) {
         return server.createContext(path);
     }
 
+    @Override
     public void removeContext(String path) throws IllegalArgumentException {
         server.removeContext(path);
     }
 
+    @Override
     public void removeContext(HttpContext context) throws IllegalArgumentException {
         server.removeContext(context);
     }
 
+    @Override
     public InetSocketAddress getAddress() {
         return server.getAddress();
     }
diff --git a/src/main/java/robaho/net/httpserver/HttpsExchangeImpl.java b/src/main/java/robaho/net/httpserver/HttpsExchangeImpl.java
index 49b5646..a674d16 100644
--- a/src/main/java/robaho/net/httpserver/HttpsExchangeImpl.java
+++ b/src/main/java/robaho/net/httpserver/HttpsExchangeImpl.java
@@ -37,83 +37,101 @@
 import com.sun.net.httpserver.HttpPrincipal;
 import com.sun.net.httpserver.HttpsExchange;
 
-class HttpsExchangeImpl extends HttpsExchange {
+final class HttpsExchangeImpl extends HttpsExchange {
 
-    ExchangeImpl impl;
+    private final ExchangeImpl impl;
 
-    HttpsExchangeImpl(ExchangeImpl impl) throws IOException {
+    HttpsExchangeImpl(ExchangeImpl impl) {
         this.impl = impl;
     }
 
+    @Override
     public Headers getRequestHeaders() {
         return impl.getRequestHeaders();
     }
 
+    @Override
     public Headers getResponseHeaders() {
         return impl.getResponseHeaders();
     }
 
+    @Override
     public URI getRequestURI() {
         return impl.getRequestURI();
     }
 
+    @Override
     public String getRequestMethod() {
         return impl.getRequestMethod();
     }
 
+    @Override
     public HttpContextImpl getHttpContext() {
         return impl.getHttpContext();
     }
 
+    @Override
     public void close() {
         impl.close();
     }
 
+    @Override
     public InputStream getRequestBody() {
         return impl.getRequestBody();
     }
 
+    @Override
     public int getResponseCode() {
         return impl.getResponseCode();
     }
 
+    @Override
     public OutputStream getResponseBody() {
         return impl.getResponseBody();
     }
 
+    @Override
     public void sendResponseHeaders(int rCode, long contentLen)
             throws IOException {
         impl.sendResponseHeaders(rCode, contentLen);
     }
 
+    @Override
     public InetSocketAddress getRemoteAddress() {
         return impl.getRemoteAddress();
     }
 
+    @Override
     public InetSocketAddress getLocalAddress() {
         return impl.getLocalAddress();
     }
 
+    @Override
     public String getProtocol() {
         return impl.getProtocol();
     }
 
+    @Override
     public SSLSession getSSLSession() {
         return impl.getSSLSession();
     }
 
+    @Override
     public Object getAttribute(String name) {
         return impl.getAttribute(name);
     }
 
+    @Override
     public void setAttribute(String name, Object value) {
         impl.setAttribute(name, value);
     }
 
+    @Override
     public void setStreams(InputStream i, OutputStream o) {
         impl.setStreams(i, o);
     }
 
+    @Override
     public HttpPrincipal getPrincipal() {
         return impl.getPrincipal();
     }
diff --git a/src/main/java/robaho/net/httpserver/HttpsServerImpl.java b/src/main/java/robaho/net/httpserver/HttpsServerImpl.java
index fd75cef..cbffa15 100644
--- a/src/main/java/robaho/net/httpserver/HttpsServerImpl.java
+++ b/src/main/java/robaho/net/httpserver/HttpsServerImpl.java
@@ -34,9 +34,9 @@
 import com.sun.net.httpserver.HttpsConfigurator;
 import com.sun.net.httpserver.HttpsServer;
 
-public class HttpsServerImpl extends HttpsServer {
+public final class HttpsServerImpl extends HttpsServer {
 
-    ServerImpl server;
+    private final ServerImpl server;
 
     HttpsServerImpl() throws IOException {
         this(new InetSocketAddress(443), 0);
@@ -47,50 +47,62 @@ public class HttpsServerImpl extends HttpsServer {
         server = new ServerImpl(this, "https", addr, backlog);
     }
 
+    @Override
     public void setHttpsConfigurator(HttpsConfigurator config) {
         server.setHttpsConfigurator(config);
     }
 
+    @Override
     public HttpsConfigurator getHttpsConfigurator() {
         return server.getHttpsConfigurator();
     }
 
+    @Override
     public void bind(InetSocketAddress addr, int backlog) throws IOException {
         server.bind(addr, backlog);
     }
 
+    @Override
     public void start() {
         server.start();
     }
 
+    @Override
     public void setExecutor(Executor executor) {
         server.setExecutor(executor);
     }
 
+    @Override
     public Executor getExecutor() {
         return server.getExecutor();
     }
 
+    @Override
     public void stop(int delay) {
         server.stop(delay);
     }
 
-    public HttpContextImpl createContext(String path, HttpHandler handler) {
+    @Override
+    public HttpContext createContext(String path, HttpHandler handler) {
         return server.createContext(path, handler);
     }
 
-    public HttpContextImpl createContext(String path) {
+    @Override
+    public HttpContext createContext(String path) {
         return server.createContext(path);
     }
 
+    @Override
     public void removeContext(String path) throws IllegalArgumentException {
         server.removeContext(path);
     }
 
+    @Override
     public void removeContext(HttpContext context) throws IllegalArgumentException {
         server.removeContext(context);
     }
 
+    @Override
     public InetSocketAddress getAddress() {
         return server.getAddress();
     }
diff --git a/src/main/java/robaho/net/httpserver/LeftOverInputStream.java b/src/main/java/robaho/net/httpserver/LeftOverInputStream.java
index 0ce99f3..8b34ccb 100644
--- a/src/main/java/robaho/net/httpserver/LeftOverInputStream.java
+++ b/src/main/java/robaho/net/httpserver/LeftOverInputStream.java
@@ -48,12 +48,13 @@ abstract class LeftOverInputStream extends FilterInputStream {
     protected boolean eof = false;
     byte[] one = new byte[1];
 
-    public LeftOverInputStream(ExchangeImpl t, InputStream src) {
+    protected LeftOverInputStream(ExchangeImpl t, InputStream src) {
         super(src);
         this.t = t;
         this.server = t.getServerImpl();
     }
 
+    @Override
     public void close() throws IOException {
         if (closed) {
             return;
@@ -64,12 +65,13 @@ public void close() throws IOException {
         }
     }
 
-    public boolean isClosed() {
+    protected boolean isClosed() {
         return closed;
     }
 
     protected abstract int readImpl(byte[] b, int off, int len) throws IOException;
 
+    @Override
     public synchronized int read() throws IOException {
         if (closed) {
             throw new EOFException("Stream is closed");
@@ -82,6 +84,7 @@ public synchronized int read() throws IOException {
         }
     }
 
+    @Override
     public synchronized int read(byte[] b, int off, int len) throws IOException {
         if (closed) {
             throw new EOFException("Stream is closed");
@@ -97,7 +100,7 @@ public synchronized int read(byte[] b, int off, int len) throws IOException {
      * is at eof (ie. all bytes were read) or false if not
      * (still bytes to be read)
      */
-    public boolean drain(long l) throws IOException {
+    protected boolean drain(long l) throws IOException {
 
         while (l > 0) {
             if (server.isFinishing()) {
@@ -113,7 +116,7 @@ public boolean drain(long l) throws IOException {
         }
         return false;
     }
-    public InputStream getRawInputStream() {
+    protected InputStream getRawInputStream() {
         return super.in;
     }
 }
diff --git a/src/main/java/robaho/net/httpserver/Request.java b/src/main/java/robaho/net/httpserver/Request.java
index a6967ce..cdf6887 100644
--- a/src/main/java/robaho/net/httpserver/Request.java
+++ b/src/main/java/robaho/net/httpserver/Request.java
@@ -35,7 +35,7 @@
 
 /**
  */
-class Request {
+final class Request {
 
     static final char CR = 13;
     static final char LF = 10;
@@ -52,23 +52,23 @@ class Request {
         requestLine = readRequestLine();
     }
 
-    public InputStream inputStream() {
+    InputStream inputStream() {
         return is;
     }
 
-    public OutputStream outputStream() {
+    OutputStream outputStream() {
         return os;
     }
 
-    static class PushbackStream {
+    static final class PushbackStream {
         private final InputStream is;
         private int pushback = -1;
         private boolean eof=false;
 
-        public PushbackStream(InputStream is) {
+        PushbackStream(InputStream is) {
             this.is = is;
         }
-        public int read() throws IOException {
+        int read() throws IOException {
             if(pushback!=-1) {
                 try {
                     return pushback;
@@ -79,7 +79,7 @@ public int read() throws IOException {
             if(eof) return -1;
             return is.read();
         }
-        public void skipWhitespace() throws IOException {
+        void skipWhitespace() throws IOException {
             int c;
             for(c=read();c==' ' || c=='\t';c=read()){}
             if(c==-1) eof=true; else pushback=c;
@@ -143,7 +143,7 @@ private static String trimmed(BufferedBuilder bb) {
     /**
      * @returns the request line or the empty string if not found
      */
-    public String requestLine() {
+    String requestLine() {
         return requestLine;
     }
 
@@ -167,7 +167,7 @@ void append(char c) {
             }
             buffer[count++]=(byte)c;
         }
-        public String trimmed() {
+        String trimmed() {
             int start=0;
             while(start<count && buffer[start]==' ') start++;
             int end=count;
diff --git a/src/main/java/robaho/net/httpserver/ServerConfig.java b/src/main/java/robaho/net/httpserver/ServerConfig.java
index 2b5fed4..0a12075 100644
--- a/src/main/java/robaho/net/httpserver/ServerConfig.java
+++ b/src/main/java/robaho/net/httpserver/ServerConfig.java
@@ -33,7 +33,7 @@
  */
 
 @SuppressWarnings("removal")
-class ServerConfig {
+final class ServerConfig {
 
     private static final int DEFAULT_IDLE_TIMER_SCHEDULE_MILLIS = 10000; // 10 sec.
 
diff --git a/src/main/java/robaho/net/httpserver/ServerImpl.java b/src/main/java/robaho/net/httpserver/ServerImpl.java
index 7440270..2ffcbfb 100644
--- a/src/main/java/robaho/net/httpserver/ServerImpl.java
+++ b/src/main/java/robaho/net/httpserver/ServerImpl.java
@@ -67,7 +67,7 @@
 /**
  * Provides implementation for both HTTP and HTTPS
  */
-class ServerImpl {
+final class ServerImpl {
 
     private final String protocol;
     private final boolean https;
@@ -108,8 +108,8 @@ class ServerImpl {
                 : IDLE_INTERVAL;
     }
 
-    private Timer timer;
-    private Logger logger;
+    private final Timer timer;
+    private final Logger logger;
     private Thread dispatcherThread;
 
     // statistics
@@ -153,7 +153,7 @@ public boolean isLoggable(LogRecord record) {
         }
     }
 
-    private class StatsHandler implements HttpHandler {
+    private final class StatsHandler implements HttpHandler {
         volatile long lastStatsTime = System.currentTimeMillis();
         volatile long lastRequestCount = 0;
         @Override
@@ -200,7 +200,7 @@ public void handle(HttpExchange exchange) throws IOException {
         }
     }
 
-    public void bind(InetSocketAddress addr, int backlog) throws IOException {
+    void bind(InetSocketAddress addr, int backlog) throws IOException {
         if (bound) {
             throw new BindException("HttpServer already bound");
         }
@@ -212,7 +212,7 @@ public void bind(InetSocketAddress addr, int backlog) throws IOException {
         bound = true;
     }
 
-    public void start() {
+    void start() {
         if (!bound || started || finished) {
             throw new IllegalStateException("server in wrong state");
         }
@@ -225,14 +225,14 @@ public void start() {
         dispatcherThread.start();
     }
 
-    public void setExecutor(Executor executor) {
+    void setExecutor(Executor executor) {
         if (started) {
             throw new IllegalStateException("server already started");
         }
         this.executor = executor;
     }
 
-    private static class DefaultExecutor implements Executor {
+    private static final class DefaultExecutor implements Executor {
         private final ExecutorService executor = Executors.newCachedThreadPool();
 
         @Override
@@ -244,11 +244,11 @@ public void shutdown() {
         }
     }
 
-    public Executor getExecutor() {
+    Executor getExecutor() {
         return executor;
     }
 
-    public void setHttpsConfigurator(HttpsConfigurator config) {
+    void setHttpsConfigurator(HttpsConfigurator config) {
         if (config == null) {
             throw new NullPointerException("null HttpsConfigurator");
         }
@@ -258,15 +258,15 @@ public void setHttpsConfigurator(HttpsConfigurator config) {
         this.httpsConfig = config;
     }
 
-    public HttpsConfigurator getHttpsConfigurator() {
+    HttpsConfigurator getHttpsConfigurator() {
         return httpsConfig;
     }
 
-    public final boolean isFinishing() {
+    boolean isFinishing() {
         return finished;
     }
 
-    public void stop(int delay) {
+    void stop(int delay) {
         if (delay < 0) {
             throw new IllegalArgumentException("negative delay parameter");
         }
@@ -302,7 +302,7 @@ public void stop(int delay) {
 
     Dispatcher dispatcher;
 
-    public HttpContextImpl createContext(String path, HttpHandler handler) {
+    HttpContextImpl createContext(String path, HttpHandler handler) {
         if (handler == null || path == null) {
             throw new NullPointerException("null handler, or path parameter");
         }
@@ -312,7 +312,7 @@ public HttpContextImpl createContext(String path, HttpHandler handler) {
         return context;
     }
 
-    public HttpContextImpl createContext(String path) {
+    HttpContextImpl createContext(String path) {
         if (path == null) {
             throw new NullPointerException("null path parameter");
         }
@@ -322,7 +322,7 @@ public HttpContextImpl createContext(String path) {
         return context;
     }
 
-    public void removeContext(String path) throws IllegalArgumentException {
+    void removeContext(String path) throws IllegalArgumentException {
         if (path == null) {
             throw new NullPointerException("null path parameter");
         }
@@ -330,7 +330,7 @@ public void removeContext(String path) throws IllegalArgumentException {
         logger.log(Level.DEBUG, "context removed: " + path);
     }
 
-    public void removeContext(HttpContext context) throws IllegalArgumentException {
+    void removeContext(HttpContext context) throws IllegalArgumentException {
         if (!(context instanceof HttpContextImpl)) {
             throw new IllegalArgumentException("wrong HttpContext type");
         }
@@ -339,7 +339,7 @@ public void removeContext(HttpContext context) throws IllegalArgumentException {
     }
 
     @SuppressWarnings("removal")
-    public InetSocketAddress getAddress() {
+    InetSocketAddress getAddress() {
         return AccessController.doPrivileged(
                 new PrivilegedAction<InetSocketAddress>() {
                     public InetSocketAddress run() {
@@ -352,7 +352,7 @@ public InetSocketAddress run() {
      * The Dispatcher is responsible for accepting any connections and then
      * using those connections to process incoming requests.
      */
-    class Dispatcher implements Runnable {
+    final class Dispatcher implements Runnable {
         public void run() {
             while (true) {
                 try {
@@ -419,7 +419,7 @@ private void closeConnection(HttpConnection conn) {
     }
 
     /* per exchange task */
-    class Exchange implements Runnable {
+    final class Exchange implements Runnable {
         final HttpConnection connection;
         InputStream rawin;
         OutputStream rawout;
@@ -647,7 +647,7 @@ private void runPerRequest() throws IOException {
         }
 
         /* used to link to 2 or more Filter.Chains together */
-        class LinkHandler implements HttpHandler {
+        static final class LinkHandler implements HttpHandler {
 
             Filter.Chain nextChain;
 
@@ -729,7 +729,7 @@ HttpServer getWrapper() {
      * Responsible for closing connections that have been idle or exceed other
      * limits
      */
-    class ConnectionCleanerTask extends TimerTask {
+    final class ConnectionCleanerTask extends TimerTask {
 
         @Override
         public void run() {
diff --git a/src/main/java/robaho/net/httpserver/StreamClosedException.java b/src/main/java/robaho/net/httpserver/StreamClosedException.java
index e90e900..cec791f 100644
--- a/src/main/java/robaho/net/httpserver/StreamClosedException.java
+++ b/src/main/java/robaho/net/httpserver/StreamClosedException.java
@@ -27,6 +27,7 @@
 
 import java.io.*;
 
-class StreamClosedException extends IOException {
+final class StreamClosedException extends IOException {
+    @Serial
     private static final long serialVersionUID = -4485921499356327937L;
 }
diff --git a/src/main/java/robaho/net/httpserver/UndefLengthInputStream.java b/src/main/java/robaho/net/httpserver/UndefLengthInputStream.java
index 0cf38f4..e906910 100644
--- a/src/main/java/robaho/net/httpserver/UndefLengthInputStream.java
+++ b/src/main/java/robaho/net/httpserver/UndefLengthInputStream.java
@@ -32,12 +32,13 @@
  * close() does not close the underlying stream
  */
 
-class UndefLengthInputStream extends LeftOverInputStream {
+final class UndefLengthInputStream extends LeftOverInputStream {
 
     UndefLengthInputStream(ExchangeImpl t, InputStream src) {
         super(t, src);
     }
 
+    @Override
     protected int readImpl(byte[] b, int off, int len) throws IOException {
 
         int n = in.read(b, off, len);
@@ -46,17 +47,21 @@ protected int readImpl(byte[] b, int off, int len) throws IOException {
         return n;
     }
 
+    @Override
     public int available() throws IOException {
         return in.available();
     }
 
+    @Override
     public boolean markSupported() {
         return false;
     }
 
+    @Override
     public void mark(int l) {
     }
 
+    @Override
     public void reset() throws IOException {
         throw new IOException("mark/reset not supported");
     }
diff --git a/src/main/java/robaho/net/httpserver/UndefLengthOutputStream.java b/src/main/java/robaho/net/httpserver/UndefLengthOutputStream.java
index 5434db6..c1563b8 100644
--- a/src/main/java/robaho/net/httpserver/UndefLengthOutputStream.java
+++ b/src/main/java/robaho/net/httpserver/UndefLengthOutputStream.java
@@ -37,15 +37,16 @@
  * The underlying connection needs to be closed afterwards.
  */
 
-class UndefLengthOutputStream extends FilterOutputStream {
+final class UndefLengthOutputStream extends FilterOutputStream {
     private boolean closed = false;
-    ExchangeImpl t;
+    private final ExchangeImpl t;
 
     UndefLengthOutputStream(ExchangeImpl t, OutputStream src) {
         super(src);
         this.t = t;
     }
 
+    @Override
     public void write(int b) throws IOException {
         if (closed) {
             throw new IOException("stream closed");
@@ -53,6 +54,7 @@ public void write(int b) throws IOException {
         out.write(b);
     }
 
+    @Override
     public void write(byte[] b, int off, int len) throws IOException {
         Objects.checkFromIndexSize(off, len, b.length);
         if (len == 0) {
@@ -64,6 +66,7 @@ public void write(byte[] b, int off, int len) throws IOException {
         out.write(b, off, len);
     }
 
+    @Override
     public void close() throws IOException {
         if (closed) {
             return;
diff --git a/src/main/java/robaho/net/httpserver/Utils.java b/src/main/java/robaho/net/httpserver/Utils.java
index 61d28b2..518a9f7 100644
--- a/src/main/java/robaho/net/httpserver/Utils.java
+++ b/src/main/java/robaho/net/httpserver/Utils.java
@@ -28,7 +28,7 @@
 /**
  * Provides utility methods for checking header field names and quoted strings.
  */
-public class Utils {
+public final class Utils {
 
     // ABNF primitives defined in RFC 7230
     private static final boolean[] TCHAR = new boolean[256];