Loading Resources from a JAR

When accessing resources embedded within a JAR archive, developers commonly encounter a discrepancy between the resource path obtained during IDE execution and when running the application via JAR. In the IDE's context, resources are accessed directly from the file system, while in the JAR environment, the path becomes jarringly adorned with the archive's prefix (e.g., "jar:/root/app.jar!/").

To resolve this issue and maintain a consistent resource access mechanism, heed the following advice:

Utilize getResourceAsStream

Eschew the temptation to load resources using FileInputStream or similar approaches. Instead, leverage the getResourceAsStream() method to retrieve a resource as an input stream, from which data can be conveniently read.

Avoid Direct File System Access

If your code relies on accessing resources as single files stored in the file system, refrain from packaging those resources within a JAR file. Consider an alternative arrangement, such as maintaining them as separate files.

Consider Temporary File Extraction

As a last resort, you might explore a hacky solution involving the following steps:

1. Check if the resource is located in a separate file within the JAR.
2. If it's not, extract the resource to a temporary file.
3. Utilize the extracted file as necessary within your application.

While this approach might be functional, its haphazard nature suggests it should be employed cautiously.