add-JSON-to-jar-using-resource-folder

Query

In Gradle Java package.

Lets say I have the following Packages:

A depends on B.

B package has JSON file. That B will read and expose the data from JSON file as java objects to package A.

Now this JSON file needs to be accessible at runtime when package A is using package B.

What are common ways to make this work in gradle java.

Solution

To make the JSON file from package B accessible at runtime when package A is using it, you need to include the JSON file in the produced JAR for package B and then use Java's classloader mechanism to read the file.

Here's how you can achieve this:

Include the JSON file in the JAR:

Ensure the JSON file is located in the src/main/resources directory of package B. Gradle's Java plugin treats files in this directory as resources and will include them in the resulting JAR when you build the project.

Your package B directory structure might look something like:
```
B/
├── src/
│   ├── main/
│   │   ├── java/
│   │   └── resources/
│   │       └── yourFile.json
│   └── test/
├── build.gradle.kts
└── settings.gradle.kts
```

Read the JSON file in package B:

Use Java's ClassLoader to read the resource from the JAR. Here's a helper method in package B to read the JSON file:

import java.io.InputStream;
import java.io.InputStreamReader;

public class BResourceReader {
    
    public InputStreamReader readJSONResource() {
        ClassLoader classLoader = getClass().getClassLoader();
        InputStream inputStream = classLoader.getResourceAsStream("yourFile.json");
        if (inputStream == null) {
            throw new RuntimeException("Cannot find resource: yourFile.json");
        }
        return new InputStreamReader(inputStream);
    }
}

Access the JSON data in package A:

Once you've included package B as a dependency in package A's build.gradle.kts, you can simply instantiate the BResourceReader class and invoke its method to get the JSON data:

import packageB.BResourceReader;

public class A {
    
    public static void main(String[] args) {
        BResourceReader reader = new BResourceReader();
        // Now use the reader to get the JSON data
        InputStreamReader jsonReader = reader.readJSONResource();
        // ... process the JSON data using your preferred library
    }
}

Add package B as a dependency for package A:

In package A's build.gradle.kts file:
```
dependencies {
    implementation(project(":B"))
}
```

TLDR:

Put the JSON file in src/main/resources of package B.
Use Java's ClassLoader to access the JSON file in package B.
Add package B as a dependency in package A's build.gradle.kts and access the JSON data by invoking the method from package B.