Source:
<code>public String build(final Path directory, final String name, final ProgressHandler handler, final BuildParameter... params) throws DockerException, InterruptedException, IOException { checkNotNull(handler, "handler"); WebTarget resource = resource().path("build"); for (final BuildParameter param : params) { resource = resource.queryParam(param.queryParam, String.valueOf(param.value)); } if (name != null) { resource = resource.queryParam("t", name); } log.debug("Auth Config {}", authConfig); AuthRegistryConfig registryConfig = null; if (authConfig == null) { <START> registryConfig = new AuthRegistryConfig("", "", "", "", "", ""); <END> } else { registryConfig = new AuthRegistryConfig(authConfig.serverAddress(), authConfig.username(), authConfig.password(), "", authConfig.email(), authConfig.serverAddress()); } log.debug("Registry Config {}", registryConfig.toConfig()); log.debug("Registry Encoded Set {}", Base64.encodeAsString(registryConfig.toConfig())); try (final CompressedDirectory compressedDirectory = CompressedDirectory.create(directory); final InputStream fileStream = Files.newInputStream(compressedDirectory.file()); final ProgressStream build = request(POST, ProgressStream.class, resource, resource.request(APPLICATION_JSON_TYPE) .header("X-Registry-Config", Base64.encodeAsString(registryConfig.toConfig())), Entity.entity(fileStream, "application/tar"))) { String imageId = null; while (build.hasNextMessage(POST, resource.getUri())) { final ProgressMessage message = build.nextMessage(POST, resource.getUri()); final String id = message.buildImageId(); if (id != null) { imageId = id; } handler.progress(message); } return imageId; } }</code><technical_language>AuthRegistryConfig.EMPTY static variable constructing a new empty instance time</technical_language>

Target:
public String build(final Path directory, final String name, final ProgressHandler handler, final BuildParameter... params) throws DockerException, InterruptedException, IOException { checkNotNull(handler, "handler"); WebTarget resource = resource().path("build"); for (final BuildParameter param : params) { resource = resource.queryParam(param.queryParam, String.valueOf(param.value)); } if (name != null) { resource = resource.queryParam("t", name); } log.debug("Auth Config {}", authConfig); AuthRegistryConfig authRegistryConfig = null; if (authConfig == null) { authRegistryConfig = AuthRegistryConfig.EMPTY; } else { authRegistryConfig = new AuthRegistryConfig(authConfig.serverAddress(), authConfig.username(), authConfig.password(), authConfig.email(), authConfig.serverAddress()); } try (final CompressedDirectory compressedDirectory = CompressedDirectory.create(directory); final InputStream fileStream = Files.newInputStream(compressedDirectory.file()); final ProgressStream build = request(POST, ProgressStream.class, resource, resource.request(APPLICATION_JSON_TYPE) .header("X-Registry-Config", authRegistryHeader(authRegistryConfig)), Entity.entity(fileStream, "application/tar"))) { String imageId = null; while (build.hasNextMessage(POST, resource.getUri())) { final ProgressMessage message = build.nextMessage(POST, resource.getUri()); final String id = message.buildImageId(); if (id != null) { imageId = id; } handler.progress(message); } return imageId; } }