Why Does getResourceAsStream() Return Null When Loading Resources from a JAR?

Solving getResourceAsStream() Issue When Returns Null

When attempting to load a text file from a packaged JAR, utilizing Class::getResourceAsStream to retrieve an InputStream may result in a null pointer exception. To rectify this, consider the following approaches:

1. Ensure Correct Path:

   Confirm that the provided path to the file matches the internal structure of the JAR. Verify that the leading slash (/) is included, and that the file name is correct.

2. Use the Correct Class Loader:

   By default, Lifepaths.class.getClass().getResourceAsStream(...) employs the system class loader, which may not have access to resources within the JAR. Instead, use Lifepaths.class.getResourceAsStream(...), which leverages the class loader that loaded the Lifepaths class, providing access to JAR resources.

3. Include Leading Slash in Resource Path:

   When invoking getResourceAsStream(name), the path must begin with a forward slash (/). This is a crucial step to ensure successful loading of resources from within the JAR.

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