diff --git a/src/main/java/org/jruby/rack/AbstractRackDispatcher.java b/src/main/java/org/jruby/rack/AbstractRackDispatcher.java
index 3c70a6f8..a49b2c81 100644
--- a/src/main/java/org/jruby/rack/AbstractRackDispatcher.java
+++ b/src/main/java/org/jruby/rack/AbstractRackDispatcher.java
@@ -42,6 +42,7 @@ public void process(RackEnvironment request, RackResponseEnvironment response)
         }
     }
 
+    @SuppressWarnings("deprecation")
     protected void handleException(
             final Exception e,
             final RackEnvironment request,
diff --git a/src/main/java/org/jruby/rack/DefaultErrorApplication.java b/src/main/java/org/jruby/rack/DefaultErrorApplication.java
index 1abd3ecb..25eab5d3 100644
--- a/src/main/java/org/jruby/rack/DefaultErrorApplication.java
+++ b/src/main/java/org/jruby/rack/DefaultErrorApplication.java
@@ -154,7 +154,7 @@ public void respond(RackResponseEnvironment response) {
         }
 
         private void log(RackLogger.Level level, String message, Throwable e) {
-            if ( context != null ) context.log(level, message, e);
+            if ( context != null ) context.log(level, (CharSequence) message, e);
         }
 
     }
diff --git a/src/main/java/org/jruby/rack/RackApplicationFactoryDecorator.java b/src/main/java/org/jruby/rack/RackApplicationFactoryDecorator.java
index 5111a2e4..418bd028 100644
--- a/src/main/java/org/jruby/rack/RackApplicationFactoryDecorator.java
+++ b/src/main/java/org/jruby/rack/RackApplicationFactoryDecorator.java
@@ -169,12 +169,7 @@ protected RackConfig getConfig() {
      * @param level the logger level
      * @param message the log message
      */
-    protected void log(final RackLogger.Level level, final String message) {
-        getContextBang().log(level, message);
-    }
-
-    @Deprecated
-    protected void log(final String level, final String message) {
+    protected void log(final RackLogger.Level level, final CharSequence message) {
         getContextBang().log(level, message);
     }
 
@@ -184,12 +179,7 @@ protected void log(final String level, final String message) {
      * @param message the log message
      * @param e the exception raised
      */
-    protected void log(final RackLogger.Level level, final String message, Exception e) {
-        getContextBang().log(level, message, e);
-    }
-
-    @Deprecated
-    protected void log(final String level, final String message, Exception e) {
+    protected void log(final RackLogger.Level level, final CharSequence message, Exception e) {
         getContextBang().log(level, message, e);
     }
 
diff --git a/src/main/java/org/jruby/rack/RackContext.java b/src/main/java/org/jruby/rack/RackContext.java
index 96d4ecbd..55105085 100644
--- a/src/main/java/org/jruby/rack/RackContext.java
+++ b/src/main/java/org/jruby/rack/RackContext.java
@@ -15,5 +15,4 @@
 public interface RackContext extends RackLogger {
     RackConfig getConfig(); /// NOTE: deprecate ?
     String getServerInfo();
-    // TODO more methods from ServletContext here ?!
 }
diff --git a/src/main/java/org/jruby/rack/RackLogger.java b/src/main/java/org/jruby/rack/RackLogger.java
index 2f30261f..91a22fde 100644
--- a/src/main/java/org/jruby/rack/RackLogger.java
+++ b/src/main/java/org/jruby/rack/RackLogger.java
@@ -18,23 +18,26 @@ enum Level {
 
     boolean isEnabled(final Level level) ;
 
-    void log(Level level, String message) ;
-    void log(Level level, String message, Throwable ex) ;
+    void log(Level level, CharSequence message) ;
 
-    default void log(String message) {
+    void log(Level level, CharSequence message, Throwable ex) ;
+
+    default void log(CharSequence message) {
         log(Level.INFO, message);
     }
 
-    default void log(String message, Throwable ex) {
+    default void log(CharSequence message, Throwable ex) {
         log(Level.ERROR, message, ex);
     }
 
-    default void log(String level, String message) {
-        log(Level.valueOf(level), message);
+    @Deprecated
+    default void log(Level level, String message) {
+        log(level, (CharSequence) message);
     }
 
-    default void log(String level, String message, Throwable ex) {
-        log(Level.valueOf(level), message, ex);
+    @Deprecated
+    default void log(Level level, String message, Throwable ex) {
+        log(level, (CharSequence) message, ex);
     }
 
     abstract class Base implements RackLogger {
diff --git a/src/main/java/org/jruby/rack/RackServletContextListener.java b/src/main/java/org/jruby/rack/RackServletContextListener.java
index cf16d34d..ef6380e7 100644
--- a/src/main/java/org/jruby/rack/RackServletContextListener.java
+++ b/src/main/java/org/jruby/rack/RackServletContextListener.java
@@ -16,7 +16,6 @@
 import org.jruby.rack.servlet.ServletRackContext;
 
 import static org.jruby.rack.DefaultRackConfig.isThrowInitException;
-import static org.jruby.rack.RackLogger.Level.*;
 
 /**
  * Web application lifecycle listener.
@@ -100,7 +99,7 @@ protected void handleInitializationException(
             throw RackInitializationException.wrap(e);
         }
         // NOTE: factory should have already logged the error ...
-        rackContext.log(ERROR, "initialization failed", e);
+        rackContext.log("initialization failed", e);
     }
 
 }
diff --git a/src/main/java/org/jruby/rack/embed/Context.java b/src/main/java/org/jruby/rack/embed/Context.java
index 41350b72..d6a7b322 100644
--- a/src/main/java/org/jruby/rack/embed/Context.java
+++ b/src/main/java/org/jruby/rack/embed/Context.java
@@ -69,58 +69,48 @@ public void setLevel(Level level) {
     }
 
     @Override
-    public void log(String message) {
+    public void log(CharSequence message) {
         logger.log(message);
     }
 
     @Override
-    public void log(String message, Throwable ex) {
+    public void log(CharSequence message, Throwable ex) {
         logger.log(message, ex);
     }
 
     @Override
-    public void log(Level level, String message) {
+    public void log(Level level, CharSequence message) {
         if ( isEnabled(level) ) logger.log(level, message);
     }
 
     @Override
-    public void log(Level level, String message, Throwable ex) {
+    public void log(Level level, CharSequence message, Throwable ex) {
         if ( isEnabled(level) ) logger.log(level, message, ex);
     }
 
-    @Override @Deprecated
-    public void log(String level, String message) {
-        log(Level.valueOf(level), message);
-    }
-
-    @Override @Deprecated
-    public void log(String level, String message, Throwable ex) {
-        log(Level.valueOf(level), message, ex);
-    }
-
     @Override
     public boolean isEnabled(Level level) {
         if ( level == null || this.level == null ) return true;
         return this.level.ordinal() <= level.ordinal();
     }
 
-
-
     private class DefaultLogger extends RackLogger.Base {
 
         @Override
-        public void log(Level level, String message) {
+        public void log(Level level, CharSequence message) {
             final PrintStream out = config.getOut();
             out.print(level); out.print(": ");
             printMessage(out, message);
+            out.flush();
         }
 
         @Override
-        public void log(Level level, String message, Throwable ex) {
+        public void log(Level level, CharSequence message, Throwable ex) {
             final PrintStream err = config.getErr();
             err.print(level); err.print(": ");
             printMessage(err, message);
             ex.printStackTrace(err);
+            err.flush();
         }
 
         @Override
diff --git a/src/main/java/org/jruby/rack/ext/Logger.java b/src/main/java/org/jruby/rack/ext/Logger.java
index b99e03ca..21c5f741 100644
--- a/src/main/java/org/jruby/rack/ext/Logger.java
+++ b/src/main/java/org/jruby/rack/ext/Logger.java
@@ -388,11 +388,11 @@ private boolean add(final int severity, final ThreadContext context,
         else if ( msg instanceof RubyException ) { // print backtrace for error
             final RubyException error = (RubyException) msg;
             error.prepareIntegratedBacktrace(context, null);
-            doLog( loggerLevel, ExceptionUtils.formatError(error).toString() );
+            doLog( loggerLevel, ExceptionUtils.formatError(error) );
             return true;
         }
         // @logdev.write(format_message(format_severity(severity), Time.now, progname, message))
-        if ( ! msg.isNil() ) doLog( loggerLevel, msg.asString() ); // TODO CharSequence ?!
+        if ( ! msg.isNil() ) doLog( loggerLevel, msg.asString() );
         return true;
     }
 
@@ -403,7 +403,8 @@ else if ( msg instanceof RubyException ) { // print backtrace for error
     @JRubyMethod(name = "<<")
     public IRubyObject append(final ThreadContext context, final IRubyObject msg) {
         final RubyString msgString = msg.asString();
-        doLog(msgString); return msgString.rubyLength(context);
+        doLog(msgString);
+        return msgString.rubyLength(context);
     }
 
     // private
@@ -462,16 +463,12 @@ public <T> T toJava(Class<T> target) {
         return super.toJava(target);
     }
 
-    private void doLog(RackLogger.Level level, String message) {
+    private void doLog(RackLogger.Level level, CharSequence message) {
         logger.log( level, message );
     }
 
-    private void doLog(RackLogger.Level level, RubyString message) {
-        logger.log( level, message.toString() );
-    }
-
     private void doLog(RubyString message) {
-        logger.log( message.toString() );
+        logger.log( message );
     }
 
     // LoggerSilence API :
diff --git a/src/main/java/org/jruby/rack/logging/CommonsLoggingLogger.java b/src/main/java/org/jruby/rack/logging/CommonsLoggingLogger.java
index 731b9a3a..16ec5f96 100644
--- a/src/main/java/org/jruby/rack/logging/CommonsLoggingLogger.java
+++ b/src/main/java/org/jruby/rack/logging/CommonsLoggingLogger.java
@@ -46,7 +46,7 @@ public boolean isEnabled(Level level) {
     }
 
     @Override
-    public void log(Level level, String message) {
+    public void log(Level level, CharSequence message) {
         if ( level == null ) { logger.info(message); return; }
         switch ( level ) {
             case DEBUG: logger.debug(message); break;
@@ -58,7 +58,7 @@ public void log(Level level, String message) {
     }
 
     @Override
-    public void log(Level level, String message, Throwable ex) {
+    public void log(Level level, CharSequence message, Throwable ex) {
         if ( level == null ) { logger.error(message, ex); return; }
         switch ( level ) {
             case DEBUG: logger.debug(message, ex); break;
diff --git a/src/main/java/org/jruby/rack/logging/JulLogger.java b/src/main/java/org/jruby/rack/logging/JulLogger.java
index 94ef209d..4d91710e 100644
--- a/src/main/java/org/jruby/rack/logging/JulLogger.java
+++ b/src/main/java/org/jruby/rack/logging/JulLogger.java
@@ -64,13 +64,13 @@ public boolean isEnabled(Level level) {
     }
 
     @Override
-    public void log(Level level, String message) {
-        logger.log( mapLevel(level, java.util.logging.Level.INFO), message );
+    public void log(Level level, CharSequence message) {
+        logger.log( mapLevel(level, java.util.logging.Level.INFO), message.toString() );
     }
 
     @Override
-    public void log(Level level, String message, Throwable e) {
-        logger.log( mapLevel(level, java.util.logging.Level.SEVERE), message, e );
+    public void log(Level level, CharSequence message, Throwable e) {
+        logger.log( mapLevel(level, java.util.logging.Level.SEVERE), message.toString(), e );
     }
 
     private static java.util.logging.Level mapLevel(
diff --git a/src/main/java/org/jruby/rack/logging/OutputStreamLogger.java b/src/main/java/org/jruby/rack/logging/OutputStreamLogger.java
index c20be662..c82ad222 100644
--- a/src/main/java/org/jruby/rack/logging/OutputStreamLogger.java
+++ b/src/main/java/org/jruby/rack/logging/OutputStreamLogger.java
@@ -60,17 +60,17 @@ public void setLevel(Level level) {
     }
 
     @Override
-    public void log(String message) {
+    public void log(CharSequence message) {
         doLog(message);
     }
 
     @Override
-    public void log(String message, Throwable ex) {
+    public void log(CharSequence message, Throwable ex) {
         doLog(message, ex);
     }
 
     @Override
-    public void log(Level level, String message) {
+    public void log(Level level, CharSequence message) {
         if ( ! isEnabled(level) ) return;
         printLevel(this, level, out);
         doLog(message);
@@ -82,13 +82,13 @@ private void doLog(final CharSequence message) {
     }
 
     @Override
-    public void log(Level level, String message, Throwable ex) {
+    public void log(Level level, CharSequence message, Throwable ex) {
         if ( ! isEnabled(level) ) return;
         printLevel(this, level, out);
         doLog(message, ex);
     }
 
-    private void doLog(final String message, final Throwable ex) {
+    private void doLog(final CharSequence message, final Throwable ex) {
         printMessage(out, message);
         ex.printStackTrace(out);
         out.flush();
diff --git a/src/main/java/org/jruby/rack/logging/ServletContextLogger.java b/src/main/java/org/jruby/rack/logging/ServletContextLogger.java
index c8d8e056..4378fe38 100644
--- a/src/main/java/org/jruby/rack/logging/ServletContextLogger.java
+++ b/src/main/java/org/jruby/rack/logging/ServletContextLogger.java
@@ -20,23 +20,23 @@ public ServletContextLogger(ServletContext context) {
     }
 
     @Override
-    public void log(String message) {
-        context.log(message);
+    public void log(CharSequence message) {
+        context.log(message.toString());
     }
 
     @Override
-    public void log(String message, Throwable ex) {
-        context.log(message, ex);
+    public void log(CharSequence message, Throwable ex) {
+        context.log(message.toString(), ex);
     }
 
     @Override
-    public void log(Level level, String message) {
-        if ( isEnabled(level) ) context.log(message);
+    public void log(Level level, CharSequence message) {
+        if ( isEnabled(level) ) context.log(message.toString());
     }
 
     @Override
-    public void log(Level level, String message, Throwable ex) {
-        if ( isEnabled(level) ) context.log(message, ex);
+    public void log(Level level, CharSequence message, Throwable ex) {
+        if ( isEnabled(level) ) context.log(message.toString(), ex);
     }
 
     @Override
diff --git a/src/main/java/org/jruby/rack/logging/Slf4jLogger.java b/src/main/java/org/jruby/rack/logging/Slf4jLogger.java
index 81d68543..4acab7ab 100644
--- a/src/main/java/org/jruby/rack/logging/Slf4jLogger.java
+++ b/src/main/java/org/jruby/rack/logging/Slf4jLogger.java
@@ -50,26 +50,26 @@ public boolean isEnabled(Level level) {
     }
 
     @Override
-    public void log(Level level, String message) {
-        if ( level == null ) { logger.info(message); return; }
+    public void log(Level level, CharSequence message) {
+        if ( level == null ) { logger.info(message.toString()); return; }
         switch ( level ) {
-            case DEBUG: logger.debug(message); break;
-            case INFO:  logger.info(message); break;
-            case WARN:  logger.warn(message); break;
-            case ERROR: logger.error(message); break;
-            case FATAL: logger.error(message); break;
+            case DEBUG: logger.debug(message.toString()); break;
+            case INFO:  logger.info(message.toString()); break;
+            case WARN:  logger.warn(message.toString()); break;
+            case ERROR: logger.error(message.toString()); break;
+            case FATAL: logger.error(message.toString()); break;
         }
     }
 
     @Override
-    public void log(Level level, String message, Throwable ex) {
-        if ( level == null ) { logger.error(message, ex); return; }
+    public void log(Level level, CharSequence message, Throwable ex) {
+        if ( level == null ) { logger.error(message.toString(), ex); return; }
         switch ( level ) {
-            case DEBUG: logger.debug(message, ex); break;
-            case INFO:  logger.info(message, ex); break;
-            case WARN:  logger.warn(message, ex); break;
-            case ERROR: logger.error(message, ex); break;
-            case FATAL: logger.error(message, ex); break;
+            case DEBUG: logger.debug(message.toString(), ex); break;
+            case INFO:  logger.info(message.toString(), ex); break;
+            case WARN:  logger.warn(message.toString(), ex); break;
+            case ERROR: logger.error(message.toString(), ex); break;
+            case FATAL: logger.error(message.toString(), ex); break;
         }
     }
 
diff --git a/src/main/java/org/jruby/rack/servlet/DefaultServletRackContext.java b/src/main/java/org/jruby/rack/servlet/DefaultServletRackContext.java
index 0627081b..6a4f1c18 100644
--- a/src/main/java/org/jruby/rack/servlet/DefaultServletRackContext.java
+++ b/src/main/java/org/jruby/rack/servlet/DefaultServletRackContext.java
@@ -213,32 +213,22 @@ public boolean isEnabled(Level level) {
     }
 
     @Override
-    public void log(String message) {
+    public void log(CharSequence message) {
         logger.log(message);
     }
 
     @Override
-    public void log(String message, Throwable e) {
+    public void log(CharSequence message, Throwable e) {
         logger.log(message, e);
     }
 
-    @Override @Deprecated
-    public void log(String level, String message) {
-        logger.log(level, message);
-    }
-
-    @Override @Deprecated
-    public void log(String level, String message, Throwable e) {
-        logger.log(level, message, e);
-    }
-
     @Override
-    public void log(Level level, String message) {
+    public void log(Level level, CharSequence message) {
         logger.log(level, message);
     }
 
     @Override
-    public void log(Level level, String message, Throwable e) {
+    public void log(Level level, CharSequence message, Throwable e) {
         logger.log(level, message, e);
     }
 
diff --git a/src/spec/java/org/jruby/rack/logging/RaiseLogger.java b/src/spec/java/org/jruby/rack/logging/RaiseLogger.java
index 188d163c..e71a9252 100644
--- a/src/spec/java/org/jruby/rack/logging/RaiseLogger.java
+++ b/src/spec/java/org/jruby/rack/logging/RaiseLogger.java
@@ -83,30 +83,33 @@ private boolean isRaise(final Level level) {
     }
 
     @Override
-    public void log(Level level, String message) {
+    public void log(Level level, CharSequence message) {
         if ( isEnabled(level) ) {
-            out.println(level + " : " + message);
+            out.print(level + " : ");
+            out.println(message);
         }
         if ( isRaise(level) ) {
-            throw new RuntimeException(message);
+            throw new RuntimeException(message.toString());
         }
     }
 
     @Override
-    public void log(Level level, String message, Throwable ex) {
+    public void log(Level level, CharSequence message, Throwable ex) {
         if ( isEnabled(level) ) {
             if ( level.ordinal() >= Level.ERROR.ordinal() ) {
-               err.println(level + " : " + message);
+               err.print(level + " : ");
+               err.println(message);
                ex.printStackTrace(err);
             }
             else {
-               out.println(level + " : " + message);
+               out.print(level + " : ");
+               out.println(message);
                ex.printStackTrace(out);
             }
         }
         if ( isRaise(level) ) {
             if ( ex instanceof RuntimeException ) throw (RuntimeException) ex;
-            throw new RuntimeException(message, ex);
+            throw new RuntimeException(message.toString(), ex);
         }
     }
 
diff --git a/src/spec/java/org/jruby/rack/mock/RackLoggingMockServletContext.java b/src/spec/java/org/jruby/rack/mock/RackLoggingMockServletContext.java
index 4e4d2438..b937c51b 100644
--- a/src/spec/java/org/jruby/rack/mock/RackLoggingMockServletContext.java
+++ b/src/spec/java/org/jruby/rack/mock/RackLoggingMockServletContext.java
@@ -30,22 +30,16 @@ public RackLoggingMockServletContext(String resourceBasePath) {
 
     private static class NullLogger extends RackLogger.Base {
 
-        @Override
-        public void log(String message) { /* NOOP */ }
-
-        @Override
-        public void log(String message, Throwable ex) { /* NOOP */ }
-
         @Override
         public boolean isEnabled(Level level) {
             return false;
         }
 
         @Override
-        public void log(Level level, String message) { /* NOOP */ }
+        public void log(Level level, CharSequence message) { /* NOOP */ }
 
         @Override
-        public void log(Level level, String message, Throwable ex) { /* NOOP */ }
+        public void log(Level level, CharSequence message, Throwable ex) { /* NOOP */ }
 
         @Override
         public Level getLevel() {