ninja-servlet/src/main/java/ninja/servlet/NinjaServletContext.java
private void enforceCorrectEncodingOfRequest() {

        String charset = NinjaConstant.UTF_8;

        String contentType = getHeader(CONTENT_TYPE);

        if (contentType != null) {
            charset = HttpHeaderUtils.getCharsetOfContentTypeOrUtf8(contentType);
        }

        try {
            httpServletRequest.setCharacterEncoding(charset);
        } catch (UnsupportedEncodingException e) {
            logger.error("Server does not support charset of content type: " + contentType);
        }

    }
private void enforceCorrectEncodingOfRequest() {

        String charset = NinjaConstant.UTF_8;

        String contentType = getHeader(CONTENT_TYPE);

        if (contentType != null) {
            charset = HttpHeaderUtils.getCharsetOfContentTypeOrUtf8(contentType);
        }

        try {
            httpServletRequest.setCharacterEncoding(charset);
        } catch (UnsupportedEncodingException e) {
            logger.error("Server does not support charset of content type: " + contentType);
        }

    }
When a servlet engine gets a content type like: "application/json" it
assumes a default encoding of iso-xxxxx.

That is not what Ninja does (and is not consistent with default encodings
of application/json and application/xml).

Therefore we'll set utf-8 as request encoding if it is not set.