diff --git a/pom.xml b/pom.xml
index c7ec0c3..9ede59f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -35,6 +35,15 @@
           <target>1.6</target>
         </configuration>
       </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-javadoc-plugin</artifactId>
+        <version>2.9</version>
+        <configuration>
+          <show>protected</show>
+          <windowtitle>Engine.IO Client API</windowtitle>
+        </configuration>
+      </plugin>
       <plugin>
         <groupId>org.codehaus.mojo</groupId>
         <artifactId>exec-maven-plugin</artifactId>
diff --git a/src/main/java/com/github/nkzawa/engineio/client/Transport.java b/src/main/java/com/github/nkzawa/engineio/client/Transport.java
index 4140d85..809aff1 100644
--- a/src/main/java/com/github/nkzawa/engineio/client/Transport.java
+++ b/src/main/java/com/github/nkzawa/engineio/client/Transport.java
@@ -57,7 +57,7 @@ public abstract class Transport extends Emitter {
         return this;
     }
 
-    public Emitter open() {
+    public Transport open() {
         if (this.readyState == CLOSED || this.readyState < 0) {
             this.readyState = OPENING;
             this.doOpen();
@@ -117,6 +117,5 @@ public abstract class Transport extends Emitter {
         public int port;
         public int policyPort;
         public Map<String, String> query;
-
     }
 }
diff --git a/src/main/java/com/github/nkzawa/engineio/client/transports/PollingXHR.java b/src/main/java/com/github/nkzawa/engineio/client/transports/PollingXHR.java
index 81d6dfb..2845e71 100644
--- a/src/main/java/com/github/nkzawa/engineio/client/transports/PollingXHR.java
+++ b/src/main/java/com/github/nkzawa/engineio/client/transports/PollingXHR.java
@@ -78,11 +78,11 @@ public class PollingXHR extends Polling {
         this.pollXhr = req;
     }
 
-    private static class Request extends Emitter {
+    public static class Request extends Emitter {
 
-        private static final String EVENT_SUCCESS = "success";
-        private static final String EVENT_DATA = "data";
-        private static final String EVENT_ERROR = "error";
+        public static final String EVENT_SUCCESS = "success";
+        public static final String EVENT_DATA = "data";
+        public static final String EVENT_ERROR = "error";
 
         private static final ExecutorService xhrService = Executors.newCachedThreadPool();
 
@@ -149,22 +149,22 @@ public class PollingXHR extends Polling {
             });
         }
 
-        public void onSuccess() {
+        private void onSuccess() {
             this.emit(EVENT_SUCCESS);
             this.cleanup();
         }
 
-        public void onData(String data) {
+        private void onData(String data) {
             this.emit(EVENT_DATA, data);
             this.onSuccess();
         }
 
-        public void onError(Exception err) {
+        private void onError(Exception err) {
             this.emit(EVENT_ERROR, err);
             this.cleanup();
         }
 
-        public void cleanup() {
+        private void cleanup() {
             if (xhr != null) {
                 xhr.disconnect();
                 xhr = null;
@@ -177,10 +177,9 @@ public class PollingXHR extends Polling {
 
         public static class Options {
 
-            String uri;
-            String method;
-            String data;
-
+            public String uri;
+            public String method;
+            public String data;
         }
     }
 }
diff --git a/src/main/java/com/github/nkzawa/engineio/client/transports/WebSocket.java b/src/main/java/com/github/nkzawa/engineio/client/transports/WebSocket.java
index 36df177..7a509ca 100644
--- a/src/main/java/com/github/nkzawa/engineio/client/transports/WebSocket.java
+++ b/src/main/java/com/github/nkzawa/engineio/client/transports/WebSocket.java
@@ -96,7 +96,7 @@ public class WebSocket extends Transport {
     }
 
     @Override
-    public void onClose() {
+    protected void onClose() {
         if (this.bufferedAmountId != null) {
             this.bufferedAmountId.cancel(true);
         }
diff --git a/src/main/java/com/github/nkzawa/engineio/parser/Parser.java b/src/main/java/com/github/nkzawa/engineio/parser/Parser.java
index e6658be..35f46bc 100644
--- a/src/main/java/com/github/nkzawa/engineio/parser/Parser.java
+++ b/src/main/java/com/github/nkzawa/engineio/parser/Parser.java
@@ -7,7 +7,7 @@ import java.util.Map;
 public class Parser {
 
     public static final int protocol = 2;
-    public static final Map<String, Integer> packets = new HashMap<String, Integer>() {{
+    private static final Map<String, Integer> packets = new HashMap<String, Integer>() {{
         put(Packet.OPEN, 0);
         put(Packet.CLOSE, 1);
         put(Packet.PING, 2);
@@ -16,7 +16,7 @@ public class Parser {
         put(Packet.UPGRADE, 5);
         put(Packet.NOOP, 6);
     }};
-    public static final Map<Integer, String> bipackets = new HashMap<Integer, String>();
+    private static final Map<Integer, String> bipackets = new HashMap<Integer, String>();
     static {
         for (Map.Entry<String, Integer> entry : packets.entrySet()) {
             bipackets.put(entry.getValue(), entry.getKey());