René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"ServiceOptions.getDefaultProjectId incorrectly defaults to GCE metadata before service account","articleBody":"When running on a GCE host, [`ServiceOptions.getDefaultProjectId()`](https://github.com/GoogleCloudPlatform/google-cloud-java/blob/master/google-cloud-clients/google-cloud-core/src/main/java/com/google/cloud/ServiceOptions.java#L332) incorrectly returns the project id from the GCE metadata server instead of defaulting to the project ID specified in the JSON credentials file pointed by the `GOOGLE_APPLICATION_CREDENTIALS` environment variable.\r\n\r\nThis seems to be due to [`getAppEngineProjectId()`](https://github.com/GoogleCloudPlatform/google-cloud-java/blob/master/google-cloud-clients/google-cloud-core/src/main/java/com/google/cloud/ServiceOptions.java#L339) returning a project id even when running outside GAE, causing `getDefaultProjectId()` to not call `getServiceAccountProjectId()`.\r\n\r\nThis seems to have been introduced in https://github.com/GoogleCloudPlatform/google-cloud-java/pull/3413 and resulted in the behavior changing from `google-cloud-core` `1.3.0` to `1.4.0`.\r\n\r\nDocumentation: \r\n* https://github.com/GoogleCloudPlatform/google-cloud-java#specifying-a-project-id\r\n* https://github.com/GoogleCloudPlatform/google-cloud-java/blob/master/google-cloud-clients/google-cloud-core/src/main/java/com/google/cloud/ServiceOptions.java#L321\r\n\r\nRepro: https://github.com/danielnorberg/google-cloud-java-default-project-bug-repro","author":{"url":"https://github.com/danielnorberg","@type":"Person","name":"danielnorberg"},"datePublished":"2018-08-06T14:26:49.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":5},"url":"https://github.com/3533/google-cloud-java/issues/3533"}