code: @Override
      public void setHeader(String hdr, String value) {
          if (null == value) {
              if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled()) {
                  Tr.debug(tc, "setHeader(" + hdr + ", null), removing header");
              }
              this.response.removeHeader(hdr);
          } else {
              this.response.setHeader(hdr, value);
          }
      }
docs: /*
  @see javax.servlet.http.HttpServletResponse#setHeader(java.lang.String, java.lang.String)