HttpPostRequestDecoder exception

Expected behavior

Actual behavior

HttpPostRequestDecoder exception

Steps to reproduce

1. Add few lines to the Netty io.netty.example.http.helloworld.HttpHelloWorldServerHandler:
   ....
   @Override
   public void channelRead0(ChannelHandlerContext ctx, HttpObject msg) {
   if (msg instanceof HttpRequest) {
   HttpRequest req = (HttpRequest) msg;
   // Lines to add:
   if (req.method() == HttpMethod.POST) {
   HttpDataFactory factory = new DefaultHttpDataFactory(DefaultHttpDataFactory.MINSIZE);
   new HttpPostRequestDecoder(factory, req);
   }
   // end

2. Launch io.netty.example.http.helloworld.HttpHelloWorldServer

3. Post the following request to the 127.0.0.1:8080 address
   Exception rised: io.netty.handler.codec.http.multipart.HttpPostRequestDecoder$ErrorDataDecoderException: Bad string ...

Request to post (here html tags are substituted by < and >):
<s:Body xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" ><TransactionDetails>0004486 (20%) 8333-33</TransactionDetails></s:Body>

Actual request is attached

It is interestiing that exception is not rised
A. without percent sign in the request
B. or if new line "\n" is inserted before <TransactionDetails> tag

Minimal yet complete reproducer code (or URL to code)

Netty version

4.1.50

JVM version (e.g. java -version)

1.8.0_131

OS version (e.g. uname -a)

Win-10, CentOS 7.3.1611

Start at io.netty.example.http.helloworld.HttpHelloWorldServerHandler and the HttpPostRequestDecoder construction described in the reproducer; run HttpHelloWorldServer with the supplied POST body on Netty 4.1.50. Trace why the percent sign causes ErrorDataDecoderException, and consider the issue resolved when the request is handled without that exception.