How to Load a File from Resources Using FileInputStream in Java?

How can I load a file from the resources directory in a Java application using FileInputStream?

FileInputStream inputStream = new FileInputStream(getClass().getClassLoader().getResource("myFile.txt").getFile());

In Java, loading a file from the resources folder can be efficiently accomplished using the FileInputStream class. This technique is commonly used in applications to access configuration files, images, or any other resource files packaged within the application's JAR or classpath.

import java.io.FileInputStream;
import java.io.IOException;

public class ResourceLoader {
    public static void main(String[] args) {
        try (FileInputStream inputStream = new FileInputStream(getClass().getClassLoader().getResource("myFile.txt").getFile())) {
            // Process the input stream
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Causes

• File is not in the correct resources folder or path is incorrect.
• ClassLoader is not set appropriately when accessing the resource.
• File is not packaged properly in the JAR during build.

Solutions

• Ensure the file is located in the appropriate resources folder of your project (e.g., src/main/resources).
• Use `getClass().getClassLoader().getResource()` to get the file URL correctly.
• Always verify that the file is included in the final JAR post-build process.

Mistake: Forgetting to check if getResource() returns null.

Solution: Always verify that `getResource()` does not return null before attempting to access its file.

Mistake: Incorrect path leading to FileNotFoundException.

Solution: Double-check the resource file's path and ensure it's correctly referenced in the code.