authentication error: missing realm in challenge

I use HttpClient 4.3.4 and will pass the proxy with DIGEST Authentication.

But AuthenticationException("missing realm in challenge") was thrown
in org.apache.http.impl.auth.DigestScheme#authenticate.

I research HTTP Header from Proxy Server.

2014/06/26 14:43:12:691 GMT+09:00 [DEBUG] headers - http-outgoing-3 <<
Proxy-Authenticate: Digest Realm="-", nonce="YjYuNGYyYmJhMzUuY2I5ZDhlZDE5M2ZlZDM
1Mjk3NGJkNTIyYjgyNTcwMjQ=", opaque="98700A3D9CE17065E2246B41035C6609", qop="auth

The keyword is "Realm".
FIrst character is UpperCase.

I research source code of org.apache.http.impl.auth.RFC2617Schem.java.
Then
protected void parseChallenge(final CharArrayBuffer buffer,
final int pos, final int len)

{ ... this.params.put(element.getName(), element.getValue()); }

public String getParameter(final String name)

{ ... return this.params.get(name.toLowerCase(Locale.ENGLISH)); }

In my case, put the name by UpperCase and get by LowerCase.
So AuthenticationException happens.

Probably in parseChallenge()

this.params.put(element.getName().toLowerCase(Locale.ENGLIEH), element.getValue());

is correct.

#HttpClient 3.x is correct.