code: @Trivial
      @Override
      public String getCharacterEncoding() {
          if (null != this.encoding) {
              return this.encoding;
          }
  
          EncodingUtils encodingUtils = connection.getEncodingUtils();
  
          String enc = null;
          // parse content-type to see if it's set there
          String type = this.request.getHeader("Content-Type");
          if (null != type) {
              enc = encodingUtils.getCharsetFromContentType(type);
              if (!encodingUtils.isCharsetSupported(enc)) {
                  enc = null;
              }
          }
  
          // now get the appropriate match (may be set in the properties)
          this.encoding = encodingUtils.getJvmConverter(enc);
  
          if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled()) {
              Tr.debug(tc, "getCharacterEncoding: set to " + this.encoding);
          }
          return this.encoding;
      }
docs: /*
  @see javax.servlet.ServletRequest#getCharacterEncoding()