diff --git a/centrifuge/src/main/java/io/github/centrifugal/centrifuge/ConfigurationError.java b/centrifuge/src/main/java/io/github/centrifugal/centrifuge/ConfigurationError.java
index 0d5ab55..a5526d5 100644
--- a/centrifuge/src/main/java/io/github/centrifugal/centrifuge/ConfigurationError.java
+++ b/centrifuge/src/main/java/io/github/centrifugal/centrifuge/ConfigurationError.java
@@ -4,6 +4,7 @@ public class ConfigurationError extends Throwable {
     private final Throwable error;
 
     ConfigurationError(Throwable error) {
+        super(error);
         this.error = error;
     }
 
diff --git a/centrifuge/src/main/java/io/github/centrifugal/centrifuge/Options.java b/centrifuge/src/main/java/io/github/centrifugal/centrifuge/Options.java
index 1d2e474..039824b 100644
--- a/centrifuge/src/main/java/io/github/centrifugal/centrifuge/Options.java
+++ b/centrifuge/src/main/java/io/github/centrifugal/centrifuge/Options.java
@@ -11,32 +11,55 @@ public String getToken() {
         return token;
     }
 
+    /**
+     * Set connection token. If your tokens expire and you want SDK to automatically
+     * refresh tokens then set ConnectionTokenGetter (see below).
+     */
     public void setToken(String token) {
         this.token = token;
     }
 
-    /* Connection token. This is a token you have to receive from your application backend. */
+    /**
+     *  Connection token. This is a token you have to receive from your application backend.
+     */
     private String token = "";
 
-    public String getName() {
-        return name;
+    public ConnectionTokenGetter getTokenGetter() {
+        return tokenGetter;
     }
 
-    public void setName(String name) {
-        this.name = name;
+    /**
+     * Set a method to extract new connection token upon expiration.
+     */
+    public void setTokenGetter(ConnectionTokenGetter tokenGetter) {
+        this.tokenGetter = tokenGetter;
     }
 
-     /**
+    private ConnectionTokenGetter tokenGetter;
+
+    public String getName() {
+        return name;
+    }
+
+    /**
      * Set client name - name of this client. This should not be unique per client – it
      * identifies client application name actually, so name should have a limited
      * number of possible values. By default this client uses "java" as a name.
      */
+    public void setName(String name) {
+        this.name = name;
+    }
+
     private String name = "java";
 
     public String getVersion() {
         return version;
     }
 
+    /**
+     * Set client version - version of application. This may be used for observability
+     * on the server (for example in analytics).
+     */
     public void setVersion(String version) {
         this.version = version;
     }
@@ -47,13 +70,19 @@ public byte[] getData() {
         return data;
     }
 
+    /**
+     * Set custom connection data. This data will be delivered to server in Connect command.
+     * For Centrifugo this may be useful in case of using connect proxy.
+     */
     public void setData(byte[] data) {
         this.data = data;
     }
 
-    /* Connect data to send to a server inside Connect command. */
     private byte[] data;
 
+    /**
+     * Set custom headers for WebSocket Upgrade request.
+     */
     public void setHeaders(Map<String, String> headers) {
         this.headers = headers;
     }
@@ -69,14 +98,22 @@ public int getTimeout() {
         return timeout;
     }
 
+    /**
+     * Set custom timeout for requests in milliseconds. By default, 5000 is used.
+     */
     public void setTimeout(int timeout) {
         this.timeout = timeout;
     }
 
+    private int timeout = 5000;
+
     public int getMinReconnectDelay() {
         return minReconnectDelay;
     }
 
+    /**
+     * Set minimal time before reconnect attempt in milliseconds. By default, 500 is used.
+     */
     public void setMinReconnectDelay(int minReconnectDelay) {
         this.minReconnectDelay = minReconnectDelay;
     }
@@ -87,24 +124,31 @@ public int getMaxReconnectDelay() {
         return maxReconnectDelay;
     }
 
+    /**
+     * Set max time between reconnect attempts in milliseconds. By default, 20000 is used.
+     */
     public void setMaxReconnectDelay(int maxReconnectDelay) {
         this.maxReconnectDelay = maxReconnectDelay;
     }
 
     private int maxReconnectDelay = 20000;
 
-    private int timeout = 5000;
-
     public int getMaxServerPingDelay() {
         return maxServerPingDelay;
     }
 
+    /**
+     * Set max time of ping delay from server in milliseconds. By default, 10000 is used.
+     */
     public void setMaxServerPingDelay(int maxServerPingDelay) {
         this.maxServerPingDelay = maxServerPingDelay;
     }
 
     private int maxServerPingDelay = 10000;
 
+    /**
+     * Set proxy to use.
+     */
     public void setProxy(Proxy proxy) {
         this.proxy = proxy;
     }
@@ -118,6 +162,9 @@ public Proxy getProxy() {
     private String proxyLogin;
     private String proxyPassword;
 
+    /**
+     * Set proxy credentials.
+     */
     public void setProxyCredentials(String login, String password) {
         this.proxyLogin = login;
         this.proxyPassword = password;
@@ -131,19 +178,13 @@ public String getProxyPassword() {
         return proxyPassword;
     }
 
-    public ConnectionTokenGetter getTokenGetter() {
-        return tokenGetter;
-    }
-
-    public void setTokenGetter(ConnectionTokenGetter tokenGetter) {
-        this.tokenGetter = tokenGetter;
-    }
-
-    private ConnectionTokenGetter tokenGetter;
-
     public Dns getDns() {
         return this.dns;
     }
+
+    /**
+     * Set custom DNS resolver..
+     */
     public void setDns(Dns dns) {
         this.dns = dns;
     }
diff --git a/centrifuge/src/main/java/io/github/centrifugal/centrifuge/PresenceResult.java b/centrifuge/src/main/java/io/github/centrifugal/centrifuge/PresenceResult.java
index 291bf08..e204ff0 100644
--- a/centrifuge/src/main/java/io/github/centrifugal/centrifuge/PresenceResult.java
+++ b/centrifuge/src/main/java/io/github/centrifugal/centrifuge/PresenceResult.java
@@ -11,5 +11,5 @@ public Map<String, ClientInfo> getClients() {
         return clients;
     }
 
-    private Map<String, ClientInfo> clients;
+    private final Map<String, ClientInfo> clients;
 }
diff --git a/centrifuge/src/main/java/io/github/centrifugal/centrifuge/RefreshError.java b/centrifuge/src/main/java/io/github/centrifugal/centrifuge/RefreshError.java
index 8d8ae40..115eda7 100644
--- a/centrifuge/src/main/java/io/github/centrifugal/centrifuge/RefreshError.java
+++ b/centrifuge/src/main/java/io/github/centrifugal/centrifuge/RefreshError.java
@@ -1,15 +1,14 @@
 package io.github.centrifugal.centrifuge;
 
-import javax.annotation.Nullable;
-
 public class RefreshError extends Throwable {
     private final Throwable error;
 
-    RefreshError(@Nullable Throwable error) {
+    RefreshError(Throwable error) {
+        super(error);
         this.error = error;
     }
 
-    public @Nullable Throwable getError() {
+    public Throwable getError() {
         return error;
     }
 }
diff --git a/centrifuge/src/main/java/io/github/centrifugal/centrifuge/ResultCallback.java b/centrifuge/src/main/java/io/github/centrifugal/centrifuge/ResultCallback.java
index 9b68458..9b8fb60 100644
--- a/centrifuge/src/main/java/io/github/centrifugal/centrifuge/ResultCallback.java
+++ b/centrifuge/src/main/java/io/github/centrifugal/centrifuge/ResultCallback.java
@@ -3,5 +3,8 @@
 import javax.annotation.Nullable;
 
 public interface ResultCallback<T> {
+    /**
+     * onDone will be called when the operation completed. Either Throwable or T will be not null.
+     */
     void onDone(@Nullable Throwable e, @Nullable T result);
 }
diff --git a/centrifuge/src/main/java/io/github/centrifugal/centrifuge/SubscriptionErrorEvent.java b/centrifuge/src/main/java/io/github/centrifugal/centrifuge/SubscriptionErrorEvent.java
index b2346fa..d263fcd 100644
--- a/centrifuge/src/main/java/io/github/centrifugal/centrifuge/SubscriptionErrorEvent.java
+++ b/centrifuge/src/main/java/io/github/centrifugal/centrifuge/SubscriptionErrorEvent.java
@@ -1,9 +1,10 @@
 package io.github.centrifugal.centrifuge;
 
-public class SubscriptionErrorEvent {
+public class SubscriptionErrorEvent extends Throwable {
     private final Throwable error;
 
     SubscriptionErrorEvent(Throwable t) {
+        super(t);
         this.error = t;
     }
 
diff --git a/centrifuge/src/main/java/io/github/centrifugal/centrifuge/SubscriptionRefreshError.java b/centrifuge/src/main/java/io/github/centrifugal/centrifuge/SubscriptionRefreshError.java
index c1a9a64..bf3055c 100644
--- a/centrifuge/src/main/java/io/github/centrifugal/centrifuge/SubscriptionRefreshError.java
+++ b/centrifuge/src/main/java/io/github/centrifugal/centrifuge/SubscriptionRefreshError.java
@@ -4,6 +4,7 @@ public class SubscriptionRefreshError extends Throwable {
     private final Throwable error;
 
     SubscriptionRefreshError(Throwable error) {
+        super(error);
         this.error = error;
     }
 
diff --git a/centrifuge/src/main/java/io/github/centrifugal/centrifuge/SubscriptionSubscribeError.java b/centrifuge/src/main/java/io/github/centrifugal/centrifuge/SubscriptionSubscribeError.java
index cd424ad..8c19968 100644
--- a/centrifuge/src/main/java/io/github/centrifugal/centrifuge/SubscriptionSubscribeError.java
+++ b/centrifuge/src/main/java/io/github/centrifugal/centrifuge/SubscriptionSubscribeError.java
@@ -4,6 +4,7 @@ public class SubscriptionSubscribeError extends Throwable {
     private final Throwable error;
 
     SubscriptionSubscribeError(Throwable error) {
+        super(error);
         this.error = error;
     }
 
diff --git a/centrifuge/src/main/java/io/github/centrifugal/centrifuge/SubscriptionTokenError.java b/centrifuge/src/main/java/io/github/centrifugal/centrifuge/SubscriptionTokenError.java
index 6686cad..965d51b 100644
--- a/centrifuge/src/main/java/io/github/centrifugal/centrifuge/SubscriptionTokenError.java
+++ b/centrifuge/src/main/java/io/github/centrifugal/centrifuge/SubscriptionTokenError.java
@@ -4,6 +4,7 @@ public class SubscriptionTokenError extends Throwable {
     private final Throwable error;
 
     SubscriptionTokenError(Throwable error) {
+        super(error);
         this.error = error;
     }
 
diff --git a/centrifuge/src/main/java/io/github/centrifugal/centrifuge/SubscriptionTokenEvent.java b/centrifuge/src/main/java/io/github/centrifugal/centrifuge/SubscriptionTokenEvent.java
index 93cf671..42b44a3 100644
--- a/centrifuge/src/main/java/io/github/centrifugal/centrifuge/SubscriptionTokenEvent.java
+++ b/centrifuge/src/main/java/io/github/centrifugal/centrifuge/SubscriptionTokenEvent.java
@@ -1,7 +1,7 @@
 package io.github.centrifugal.centrifuge;
 
 public class SubscriptionTokenEvent {
-    private String channel;
+    final private String channel;
 
     public SubscriptionTokenEvent(String channel) {
         this.channel = channel;
@@ -10,8 +10,4 @@ public SubscriptionTokenEvent(String channel) {
     public String getChannel() {
         return channel;
     }
-
-    void setChannel(String channel) {
-        this.channel = channel;
-    }
 }
diff --git a/centrifuge/src/main/java/io/github/centrifugal/centrifuge/TokenError.java b/centrifuge/src/main/java/io/github/centrifugal/centrifuge/TokenError.java
index 300709a..68148eb 100644
--- a/centrifuge/src/main/java/io/github/centrifugal/centrifuge/TokenError.java
+++ b/centrifuge/src/main/java/io/github/centrifugal/centrifuge/TokenError.java
@@ -4,6 +4,7 @@ public class TokenError extends Throwable {
     private final Throwable error;
 
     TokenError(Throwable error) {
+        super(error);
         this.error = error;
     }
 
diff --git a/centrifuge/src/main/java/io/github/centrifugal/centrifuge/UnclassifiedError.java b/centrifuge/src/main/java/io/github/centrifugal/centrifuge/UnclassifiedError.java
index ae4158a..a9b6ec2 100644
--- a/centrifuge/src/main/java/io/github/centrifugal/centrifuge/UnclassifiedError.java
+++ b/centrifuge/src/main/java/io/github/centrifugal/centrifuge/UnclassifiedError.java
@@ -4,6 +4,7 @@ public class UnclassifiedError extends Throwable {
     private final Throwable error;
 
     UnclassifiedError(Throwable error) {
+        super(error);
         this.error = error;
     }