Solved some SpotBugs issues

Author: bbottema

src/main/java/org/bbottema/javasocksproxyserver/AuthConstants.java

@@ -1,13 +1,13 @@
 package org.bbottema.javasocksproxyserver;
 
-public interface AuthConstants {
-    byte AUTH_VERSION = 0x01;
-    byte[] AUTH_USER_PASS_SUCCESS = new byte[]{AUTH_VERSION, 0x00};
+public class AuthConstants {
+    static final byte AUTH_VERSION = 0x01;
+    static final byte[] AUTH_USER_PASS_SUCCESS = new byte[]{AUTH_VERSION, 0x00};
     // 0x00 denotes success, any other value denotes failure
-    byte[] AUTH_USER_PASS_FAILED = new byte[]{AUTH_VERSION, 0x01};
+    static final byte[] AUTH_USER_PASS_FAILED = new byte[]{AUTH_VERSION, 0x01};
 
-    byte TYPE_NO_AUTH = 0x00;
-    byte TYPE_USER_PASS_AUTH = 0x02;
+    public static final byte TYPE_NO_AUTH = 0x00;
+    public static final byte TYPE_USER_PASS_AUTH = 0x02;
 
-    byte NONE_ACCEPTED = (byte) 0xff;
+    public static final byte NONE_ACCEPTED = (byte) 0xff;
 }

src/main/java/org/bbottema/javasocksproxyserver/SocksServer.java

@@ -35,7 +35,7 @@ public SocksServer(int listenPort, ServerSocketFactory factory) {
 		this.factory = factory;
 	}
 
-	public SocksServer setAuthenticator(Authenticator authenticator) {
+	public synchronized SocksServer setAuthenticator(Authenticator authenticator) {
 		this.authenticator = authenticator;
 		return this;
 	}
@@ -90,8 +90,8 @@ public void run() {
 		protected void handleClients(int port) throws IOException {
 			final ServerSocket listenSocket = serverSocketFactory.createServerSocket(port);
 			listenSocket.setSoTimeout(SocksConstants.LISTEN_TIMEOUT);
-			
-			LOGGER.debug("SOCKS server listening at port: " + listenSocket.getLocalPort());
+
+            LOGGER.debug("SOCKS server listening at port: {}", listenSocket.getLocalPort());
 
 			while (true) {
 				synchronized (SocksServer.this) {
@@ -113,7 +113,7 @@ private void handleNextClient(ServerSocket listenSocket) {
 			try {
 				final Socket clientSocket = listenSocket.accept();
 				clientSocket.setSoTimeout(SocksConstants.DEFAULT_SERVER_TIMEOUT);
-				LOGGER.debug("Connection from : " + Utils.getSocketInfo(clientSocket));
+                LOGGER.debug("Connection from : {}", Utils.getSocketInfo(clientSocket));
 				new Thread(new ProxyHandler(clientSocket, authenticator)).start();
 			} catch (InterruptedIOException e) {
 				//	This exception is thrown when accept timeout is expired

src/main/java/org/bbottema/javasocksproxyserver/auth/UsernamePasswordAuthenticator.java

@@ -2,6 +2,8 @@
 
 import org.bbottema.javasocksproxyserver.AuthConstants;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 public abstract class UsernamePasswordAuthenticator extends Authenticator {
 
     private final boolean acceptNoAuthMode;
@@ -29,7 +31,7 @@ public byte accept(byte[] authTypes) {
 
     @Override
     public boolean validate(byte[] username, byte[] password) {
-        return validate(new String(username), new String(password));
+        return validate(new String(username, UTF_8), new String(password, UTF_8));
     }
 
     public abstract boolean validate(String username, String password);