# Integrate executable Java code in your blog posts, part 2: How to use dependencies

> Not only "simple" Java code can be added: a more complex class with a record and Maven dependencies can be created and executed on Foojay.

- URL: https://foojay.io/today/integrate-executable-java-code-in-your-blog-posts-part-2-how-to-use-dependencies/
- Published: 2023-12-15
- Authors: Frank Delporte
- Categories: Foojay, Tutorials


In a previous post, we [explained how you can add executable Java code to your posts here on Foojay](https://foojay.io/today/integrate-executable-java-code-in-your-blog-posts/), by using JDoodle. In this post, you will learn how you can extend this with one or more libraries.

## Define Dependencies

To integrate Java code in your post or page that needs dependencies, list their Maven coordinates in the shortcode's `libs` parameter.

```
{{</* jdoodle libs="mavenlib1,mavenlib2" */>}}

     // This is the place to put your Java code

{{</* /jdoodle */>}}
```

The shortcode adds Foojay's own JDoodle client id for you, and that id only works on the Foojay website. Create your own [account on the JDoodle site](https://www.jdoodle.com) if you want to use this functionality on another website.

## Example Application

For example, let's use the Jackson library to parse JSON.

```
{{</* jdoodle libs="com.fasterxml.jackson.core:jackson-annotations:2.16.0,com.fasterxml.jackson.core:jackson-core:2.16.0,com.fasterxml.jackson.core:jackson-databind:2.16.0" */>}}
import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonValue;
import com.fasterxml.jackson.databind.ObjectMapper;

import java.io.IOException;
import java.time.Instant;
import java.time.ZoneId;
import java.time.ZonedDateTime;
import java.util.Arrays;

public class JsonParsing {
    public static void main (String[] args) {
        var json = """
                [
                    { 
                        "level": 0,
                        "timestamp": 1675867184342,
                        "message": "Program started"
                    },
                    {
                        "level": 5,
                        "timestamp": 1675867185921,
                        "message": "File X not found"
                    },
                    {
                        "level": 9,
                        "timestamp": 1675867186357,
                        "message": "Error at line Y"
                    }
                ]
                """;

        try {
            ObjectMapper objectMapper = new ObjectMapper();
            LogMessage[] logMessages = objectMapper.readValue(json, LogMessage[].class);

            System.out.println("Data loaded from JSON:\n");

            for (LogMessage logMessage : logMessages) {
                System.out.println("Log message at " + logMessage.timestamp()
                        + "\n\tSeverity: " + logMessage.level()
                        + "\n\tMessage: " + logMessage.message());
            }
        } catch (IOException ex) {
            System.err.println("Json processing exception: " + ex.getMessage());
        }
    }

    record LogMessage(int level, Long timestamp, String message) { }
}
{{</* /jdoodle */>}}
```

Will produce the following output. Hit the "Execute" button to run the code.

{{< jdoodle libs="com.fasterxml.jackson.core:jackson-annotations:2.16.0,com.fasterxml.jackson.core:jackson-core:2.16.0,com.fasterxml.jackson.core:jackson-databind:2.16.0" >}}
import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonValue;
import com.fasterxml.jackson.databind.ObjectMapper;

import java.io.IOException;
import java.time.Instant;
import java.time.ZoneId;
import java.time.ZonedDateTime;
import java.util.Arrays;

public class JsonParsing {
    public static void main (String[] args) {
        var json = """
                [
                    { 
                        "level": 0,
                        "timestamp": 1675867184342,
                        "message": "Program started"
                    },
                    {
                        "level": 5,
                        "timestamp": 1675867185921,
                        "message": "File X not found"
                    },
                    {
                        "level": 9,
                        "timestamp": 1675867186357,
                        "message": "Error at line Y"
                    }
                ]
                """;

        try {
            ObjectMapper objectMapper = new ObjectMapper();
            LogMessage[] logMessages = objectMapper.readValue(json, LogMessage[].class);

            System.out.println("Data loaded from JSON:\n");

            for (LogMessage logMessage : logMessages) {
                System.out.println("Log message at " + logMessage.timestamp()
                        + "\n\tSeverity: " + logMessage.level()
                        + "\n\tMessage: " + logMessage.message());
            }
        } catch (IOException ex) {
            System.err.println("Json processing exception: " + ex.getMessage());
        }
    }

    record LogMessage(int level, Long timestamp, String message) { }
}
{{< /jdoodle >}}

**Notice you can also select Java 21 now to execute this code!**

## Conclusion

Not only "simple" Java code can be added to blog posts. As we illustrated here, a more complex class with a record and Maven dependencies can be created and executed within a webpage.

In part 3 of the JDoodle posts, that will be published soon, we'll talk with the creator of JDoodle, [Gokul Chandrasekaran](https://www.linkedin.com/in/gokulchandrasekaran-jdoodle?miniProfileUrn=urn%3Ali%3Afs_miniProfile%3AACoAAANJfEYBcRBniUXnKroUIsiftQzJwkwXl4I).