diff --git a/libai/src/main/java/ai/api/AIDataService.java b/libai/src/main/java/ai/api/AIDataService.java
index 384f57a..5cd9d78 100644
--- a/libai/src/main/java/ai/api/AIDataService.java
+++ b/libai/src/main/java/ai/api/AIDataService.java
@@ -34,8 +34,6 @@
 import java.io.InputStream;
 import java.lang.reflect.Type;
 import java.net.*;
-import java.nio.charset.Charset;
-import java.nio.charset.StandardCharsets;
 import java.util.Calendar;
 import java.util.Collection;
 import java.util.Collections;
@@ -58,7 +56,6 @@
 public class AIDataService {
 
     private static final Logger Log = LogManager.getLogger(AIDataService.class);
-    private static final Charset DEFAULT_CHARSET = StandardCharsets.UTF_8;
     private static final AIServiceContext UNDEFINED_SERVICE_CONTEXT = null;
     private static final String REQUEST_METHOD_POST = "POST";
     private static final String REQUEST_METHOD_DELETE = "DELETE";
@@ -668,11 +665,11 @@ protected String doTextRequest(final String endpoint,
             connection.connect();
 
             final BufferedOutputStream outputStream = new BufferedOutputStream(connection.getOutputStream());
-            IOUtils.writeAll(queryData, outputStream, DEFAULT_CHARSET);
+            IOUtils.writeAll(queryData, outputStream);
             outputStream.close();
 
             final InputStream inputStream = new BufferedInputStream(connection.getInputStream());
-            final String response = IOUtils.readAll(inputStream, DEFAULT_CHARSET);
+            final String response = IOUtils.readAll(inputStream);
             inputStream.close();
 
             return response;
@@ -681,7 +678,7 @@ protected String doTextRequest(final String endpoint,
                 try {
                     final InputStream errorStream = connection.getErrorStream();
                     if (errorStream != null) {
-                        final String errorString = IOUtils.readAll(errorStream, DEFAULT_CHARSET);
+                        final String errorString = IOUtils.readAll(errorStream);
                         Log.debug(errorString);
                         return errorString;
                     }
@@ -874,12 +871,12 @@ protected <TRequest,TResponse> TResponse doRequest(
 
             if (queryData != null) {
 	            final BufferedOutputStream outputStream = new BufferedOutputStream(connection.getOutputStream());
-	            IOUtils.writeAll(queryData, outputStream, DEFAULT_CHARSET);
+	            IOUtils.writeAll(queryData, outputStream);
 	            outputStream.close();
             }
 
             final InputStream inputStream = new BufferedInputStream(connection.getInputStream());
-            final String response = IOUtils.readAll(inputStream, DEFAULT_CHARSET);
+            final String response = IOUtils.readAll(inputStream);
             inputStream.close();
             
             try {
@@ -898,7 +895,7 @@ protected <TRequest,TResponse> TResponse doRequest(
                 try {
                     final InputStream errorStream = connection.getErrorStream();
                     if (errorStream != null) {
-                        final String errorString = IOUtils.readAll(errorStream, DEFAULT_CHARSET);
+                        final String errorString = IOUtils.readAll(errorStream);
                         Log.debug(errorString);
                         throw new AIServiceException(errorString, e);
                     }
diff --git a/libai/src/main/java/ai/api/http/HttpClient.java b/libai/src/main/java/ai/api/http/HttpClient.java
index 88528a2..0e85142 100644
--- a/libai/src/main/java/ai/api/http/HttpClient.java
+++ b/libai/src/main/java/ai/api/http/HttpClient.java
@@ -30,8 +30,6 @@
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.net.HttpURLConnection;
-import java.nio.charset.Charset;
-import java.nio.charset.StandardCharsets;
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
@@ -41,7 +39,6 @@ public class HttpClient {
 	private static final Logger Log = LogManager.getLogger(HttpClient.class);
     private static final int CHUNK_LENGTH = 2048;
     private static final int BUFFER_LENGTH = 4096;
-    private static final Charset DEFAULT_CHARSET = StandardCharsets.UTF_8;
 
     /**
      *  Cannot be <code>null</code>
@@ -149,7 +146,7 @@ public void finishMultipart() throws IOException {
      */
     public String getResponse() throws IOException {
         final InputStream inputStream = new BufferedInputStream(connection.getInputStream());
-        final String response = IOUtils.readAll(inputStream, DEFAULT_CHARSET);
+        final String response = IOUtils.readAll(inputStream);
         inputStream.close();
         return response;
     }
@@ -158,7 +155,7 @@ public String getErrorString() {
         try {
             final InputStream inputStream = new BufferedInputStream(connection.getErrorStream());
             final String response;
-            response = IOUtils.readAll(inputStream, DEFAULT_CHARSET);
+            response = IOUtils.readAll(inputStream);
             inputStream.close();
             return response;
         } catch (final IOException e) {
diff --git a/libai/src/main/java/ai/api/util/IOUtils.java b/libai/src/main/java/ai/api/util/IOUtils.java
index 5f8d3ff..e3d56dc 100644
--- a/libai/src/main/java/ai/api/util/IOUtils.java
+++ b/libai/src/main/java/ai/api/util/IOUtils.java
@@ -15,6 +15,7 @@
 public class IOUtils {
 
 	private static final int DEFAULT_BUFFER_SIZE = 4096;
+	private static final String DEFAULT_CHARSET = "UTF-8";
 	
 	/**
 	 * Write string to byte stream
@@ -25,11 +26,36 @@ public class IOUtils {
 	 */
 	public static void writeAll(String data, OutputStream outputStream, Charset charset)
 		throws IOException 
+	{
+		writeAll(data, outputStream, charset.name());
+	}
+	
+	/**
+	 * Write string to byte stream
+	 * @param data Source string
+	 * @param outputStream Output stream
+	 * @param charset Convert string to bytes according to given
+	 * @throws IOException
+	 */
+	public static void writeAll(String data, OutputStream outputStream, String charset)
+		throws IOException 
 	{
 		if ((data != null) && (data.length() > 0)) {
 			outputStream.write(data.getBytes(charset));
 		}
 	}
+	
+	/**
+	 * Write string to byte stream
+	 * @param data Source string
+	 * @param outputStream Output stream
+	 * @throws IOException
+	 */
+	public static void writeAll(String data, OutputStream outputStream)
+		throws IOException 
+	{
+		writeAll(data, outputStream, DEFAULT_CHARSET);
+	}
 
 	/**
 	 * Read all stream byte data into {@link String}
@@ -39,11 +65,32 @@ public static void writeAll(String data, OutputStream outputStream, Charset char
 	 * @throws IOException
 	 */
 	public  static String readAll(InputStream inputStream, Charset charset) throws IOException {
+		return readAll(inputStream, charset.name());
+	}
+	
+	/**
+	 * Read all stream byte data into {@link String}
+	 * @param inputStream Source stream
+	 * @param charset Convert bytes to chars according to given
+	 * @return Empty {@link String} if there was no data in stream
+	 * @throws IOException
+	 */
+	public  static String readAll(InputStream inputStream, String charset) throws IOException {
 		try (InputStreamReader streamReader = new InputStreamReader(inputStream, charset)) {
 			return readAll(streamReader);
 		}
 	}
 	
+	/**
+	 * Read all stream byte data into {@link String}
+	 * @param inputStream Source stream
+	 * @return Empty {@link String} if there was no data in stream
+	 * @throws IOException
+	 */
+	public  static String readAll(InputStream inputStream) throws IOException {
+		return readAll(inputStream, DEFAULT_CHARSET);
+	}
+	
 	/**
 	 * Read all chars into String
 	 * @param streamReader Input stream reader