code: public X509Certificate[] getSignerChain() {
          if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled())
              Tr.debug(tc, "getSignerChain");
          return signer == null ? null : signer.clone();
      }
docs: Query the signer chain set on this context.
  
  @return X509Certificate[] - null if not set