code: public void setClientAlias(String alias) throws Exception {
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
              Tr.entry(tc, "setClientAlias", new Object[] { alias });
          if (!ks.containsAlias(alias)) {
              String keyFileName = config.getProperty(Constants.SSLPROP_KEY_STORE);
              String tokenLibraryFile = config.getProperty(Constants.SSLPROP_TOKEN_LIBRARY);
              String location = keyFileName != null ? keyFileName : tokenLibraryFile;
  
              String message = TraceNLSHelper.getInstance().getFormattedMessage("ssl.client.alias.not.found.CWPKI0023E", new Object[] { alias, location },
                                                                                "Client alias " + alias + " not found in keystore.");
              Tr.error(tc, "ssl.client.alias.not.found.CWPKI0023E", new Object[] { alias, location });
              throw new IllegalArgumentException(message);
          }
          this.clientAlias = alias;
  
          if (customKM != null && customKM instanceof KeyManagerExtendedInfo)
              ((KeyManagerExtendedInfo) customKM).setKeyStoreClientAlias(alias);
  
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
              Tr.exit(tc, "setClientAlias");
      }
docs: Set the client alias value for the given slot number.
  
  @param alias
  @param slotnum
  @throws Exception