private static void populateExtensions(Wallet wallet, Protos.Wallet.Builder walletBuilder) { for (WalletExtension extension : wallet.getExtensions().values()) { Protos.Extension.Builder proto = Protos.Extension.newBuilder(); proto.setId(extension.getWalletExtensionID()); proto.setMandatory(extension.isWalletExtensionMandatory()); proto.setData(ByteString.copyFrom(extension.serializeWalletExtension())); walletBuilder.addExtension(proto); } }