Why Does `getResourceAsStream` Return Null When Accessing Resources in a JAR, and How Can I Fix It?

Resolving getResourceAsStream's Null Output

When attempting to retrieve a text file from within a packaged JAR using Class::getResourceAsStream returns null, it indicates issues with the resource loading mechanism. The following solution addresses this problem:

1. Modified Resource Loading: Instead of using Lifepaths.class.getClass().getResourceAsStream(...), which invokes the system class loader (which often lacks visibility into packaged resources), utilize Lifepaths.class.getResourceAsStream(...) directly. This ensures that resources are loaded by the class loader that loaded Lifepaths, allowing it to access the packaged resources.
2. Leading Slash: When specifying the resource path in getResourceAsStream(name), it is essential to prefix it with a forward slash (/). This is not always necessary but has been observed to resolve potential issues.

By implementing these modifications, the provided code should successfully load and print the contents of the text file from within the JAR package.

The above is the detailed content of Why Does `getResourceAsStream` Return Null When Accessing Resources in a JAR, and How Can I Fix It?. For more information, please follow other related articles on the PHP Chinese website!