https://github.com/OpenFeign/feign/issues/2540

FeignException does not throw exception during extracting response charset now.

These content types are all valid:
text/html;charset=utf-8
text/html;charset=UTF-8
Text/HTML;Charset="utf-8"
text/html; charset="utf-8"

core/src/main/java/feign/FeignException.java

@@ -21,6 +21,7 @@
 import java.nio.ByteBuffer;
 import java.nio.CharBuffer;
 import java.nio.charset.Charset;
+import java.nio.charset.IllegalCharsetNameException;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Map;
@@ -29,6 +30,7 @@
 import java.util.regex.Pattern;
 import static feign.Util.*;
 import static java.lang.String.format;
+import static java.util.regex.Pattern.CASE_INSENSITIVE;
 
 /**
  * Origin exception type for all Http Apis.
@@ -519,14 +521,18 @@ private static Charset getResponseCharset(Map<String, Collection<String>> header
         return null;
       }
 
-      Pattern pattern = Pattern.compile(".*charset=([^\\s|^;]+).*");
+      Pattern pattern = Pattern.compile(".*charset=\"?([^\\s|^;|^\"]+).*", CASE_INSENSITIVE);
       Matcher matcher = pattern.matcher(strings.iterator().next());
       if (!matcher.lookingAt()) {
         return null;
       }
 
       String group = matcher.group(1);
-      if (!Charset.isSupported(group)) {
+      try {
+        if (!Charset.isSupported(group)) {
+          return null;
+        }
+      } catch (IllegalCharsetNameException ex) {
         return null;
       }
       return Charset.forName(group);