Three ways Amazon Q Developer agent for code transformation accelerates Java upgrades

When Amazon Web Services (AWS) launched Amazon Q Developer agent for code transformation as a preview last year to upgrade Java applications, we saw many organizations desire to significantly accelerate their Java upgrades. Previously, these upgrades were considered daunting, a time-consuming manual task requiring weeks if not months of effort and with Amazon Q Developer they could significantly reduce that burden. Companies such as Toyota, Novacamp, Pragma and Persistent saw productivity gains not only in reducing the amount of time the upgrades would take, but re-prioritizing that time saved into other business priorities related to the software development lifecycle (SDLC). In addition, a small team of AWS developers upgraded over 1000 carefully chosen applications from multiple independent services. These applications used less than 10 dependencies and required minimal mandatory changes to the application code for the upgrade. While we saw a high degree of upgrade success for simpler applications, we also heard from customers who wanted even more capabilities in the Amazon Q Developer agent for code transformation. They expected the agent to upgrade their libraries to the latest major versions, replace deprecated API calls, and provide more explainability of changes made.

We added these and more capabilities to the agent at General Availability (GA). Today, we’re going into detail on the following four categories for what Amazon Q Developer can do for your Java upgrades: major version upgrades of popular frameworks, directly replacing deprecated API calls on your behalf, clear explainability on code changes, and using some examples of our unprecedented AI technology powered by Amazon Bedrock, that is capable, for example, of correcting more compilation errors that can be encountered when attempting the build in Java 17.

This blog post will dive deeper into these three ways we improved the product experience through an example application. You can download the application from this GitHub repository.

About the application

This is a Java 1.8 based microservice application which displays free list of movies for the month based on configuration stored in AWS AppConfig service using AWS SDK. This application was first open sourced in 2020 and uses legacy versions of libraries such as Spring Boot 2.x, Log4j 2.13.x, Mockito 1.x, Javax and Junit 4. You can download the sample project to try it for yourself.

(1) Popular framework upgrades

While Spring Boot version 2.7 is compatible with Java 17, Amazon Q Developer agent for code transformation can bring your applications up to version 3.2. This has been helpful because it can be time consuming to correct all the changes in annotations and code implementation that are no longer compatible when going into the new major version upgrade. Moreover, this version of Spring Boot provides improved observability, performance improvements, modernized security, and overall enhanced development experience. Let’s dive into some examples of where you see Amazon Q Developer accelerate some of this heavy lifting during the upgrade process.

When working with file uploads in Spring Boot v2, you would typically use the @RequestParam("file") annotation to bind the uploaded file to a method parameter. However, in Spring Boot v3.2, this approach has been updated to better align with the Jakarta EE specifications. Instead of using a plain String parameter, you’ll need to use the MultipartFile class from the org.springframework.web.multipart package. Here is an example before and after code transformation with Amazon Q Developer:

Java 8 code with Spring v2

@RequestMapping(value = "/movies/{movie}/edit", method = POST)
public String processUpdateMovie(@Valid Movie movie, BindingResult result, @PathVariable("movieId") int movieId) { ...
} 

Java 17 code upgraded by Amazon Q Developer with Spring v3

@PostMapping("/movies/{movie}/edit")
public String processUpdateMovie(@Valid Movie movie, BindingResult result, @PathVariable int movieId) { ... }

Associated dependency updates in pom.xml

<parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.0.5.RELEASE</version>
</parent>

to

<parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>3.2.5</version>
</parent>

The following lists some common libraries we’ve seen you all use, with the corresponding compatible version in Java 8 and what we’re capable of upgrading to using Q Developer. This list isn’t comprehensive of all libraries, the intent is to show some common ones. This could change in the future and is up-to-date as of the time of this publication.

Let’s review a few examples from the Sample project.

Java 8 code with Junit 4

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
import com.amazonaws.samples.appconfig.movies.MoviesController; @RunWith(SpringRunner.class)
@SpringBootTest
public class MovieTest { ...
}

@Before
public void setUp() { MockitoAnnotations.initMocks(this); moviesController = new MoviesController(); moviesController.env = env;
}

<dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.13.1</version> <scope>test</scope>
</dependency>

Java 17 code upgraded by Amazon Q Developer with Junit 5:

import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;
import com.amazonaws.samples.appconfig.movies.MoviesController; @SpringBootTest
public class MovieTest { ...
}

@BeforeEach
public void setUp() { MockitoAnnotations.initMocks(this); moviesController = new MoviesController(); moviesController.env = env;
}

<dependency> <groupId>org.junit.jupiter</groupId> <artifactId>junit-jupiter</artifactId> <scope>test</scope>
</dependency>

(2) Deprecated APIs

One of the biggest challenges organizations face when upgrading to a newer version of Java is dealing with deprecated APIs. As new language features and libraries are introduced, older APIs are often marked as deprecated and eventually removed in subsequent releases. This can lead to compilation errors and compatibility issues, requiring developers to manually identify and replace these deprecated APIs throughout their codebase – a time-consuming and error-prone process.

In our sample application, you will see a variety of deprecated APIs that are addressed by Q Developer as an output of the transformation to Java 17. Here are some examples:

Before:

bd.divide(bd2, BigDecimal.ROUND_DOWN);
bd.divide(bd2, 1, BigDecimal.ROUND_CEILING); 

After:

bd.divide(bd2, RoundingMode.DOWN);
bd.divide(bd2, 1, RoundingMode.CEILING);

Before:

String enc1 = new sun.misc.BASE64Encoder().encode(bytes);

After:

import java.util.Base64;
String enc1 = Base64.getEncoder().encodeToString(bytes);

Before:

import javax.security.cert.*;

After:

import java.security.cert.*;

Before:

import static org.mockito.Matchers.anyInt;
...
when(mocklist.get(anyInt())).thenReturn("Movies");

After:

import static org.mockito.ArgumentMatchers.anyInt;
...
when(mocklist.get(anyInt())).thenReturn("Movies");

Java versions before 15 required explicit line terminators, string concatenations, and delimiters to embed multi-line code snippets. Java 15 introduced text blocks to simplify embedding code snippets and text sequences, particularly useful for literals like HTML, JSON, and SQL. Text blocks are an alternative string representation that can replace traditional double-quoted string literals, allowing multi-line strings without explicit line terminators or concatenations. Amazon Q Developer agent for code transformation will migrate your complex multi-line text which not so readable to text blocks.

Before:

private static String getMovieItemsHtml(Movie[] movies) { StringBuilder movieItemsHtml = new StringBuilder(); for (Movie movie : movies) { movieItemsHtml.append("<div class='movie-item'>" + "<p>ID: ").append(movie.getId()).append("</p>" + "<h3>").append(movie.getMovieName()).append("</h3>" + "<hr width=\"100%\" size=\"2\" color=\"blue\" noshade>" + "</div>"); } return movieItemsHtml.toString(); }

After:

private static String getMovieItemsHtml(Movie[] movies) { StringBuilder movieItemsHtml = new StringBuilder(); for (Movie movie : movies) { movieItemsHtml.append(""" <div class='movie-item'>\ <p>ID: \ """).append(movie.getId()).append(""" </p>\ <h3>\ """).append(movie.getMovieName()).append(""" </h3>\ <hr width="100%" size="2" color="blue" noshade>\ </div>\ """); } return movieItemsHtml.toString(); }

Including these examples above in the sample app, Q Developer supports a wide range of abilities to address deprecated APIs across various domains, including primitive type constructors and conversions, character and string utilities, date and time handling, mathematical operations, networking and sockets, security and cryptography, concurrent programming and atomics, reflection and bytecode generation, as well as a significant number of deprecated methods related to Swing and AWT components. Whether it’s replacing outdated methods for handling dates, encoding URLs, or working with BigDecimal arithmetic, we can automatically update your code to use their modern equivalents. It also addresses deprecations in areas like multicast sockets, atomic variables, and even bytecode generation using ASM.

With the Q Developer agent for code transformation, we’ve made it easier than ever to handle deprecated APIs during your Java 17 migration. Q Developer is capable of automatically detecting and replacing deprecated API calls with their modern equivalents, saving you countless hours of manual effort and reducing the risk of introducing bugs or regressions.

(3) Unprecedented AI technology

Even after addressing deprecated APIs and framework upgrades, the process of migrating to a new Java version can still encounter compilation errors or unexpected behavior. These issues can arise from subtle changes in language semantics, incompatibilities between libraries, or other factors that are difficult to anticipate and diagnose.

To tackle this challenge, the Q Developer agent for code transformation leverages our self-debugging technology powered by Bedrock which analyzes the context of compilation errors and is capable of implementing targeted code modifications to resolve them. Here are some examples.

Java 1.8 with javax.security.X509Certificate:

import javax.security.cert.*;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;
import java.util.Date; public class Security { public Certificate getCertificate(File certFile) throws CertificateExpiredException, CertificateNotYetValidException { X509Certificate cert = null; try { InputStream inStream = new FileInputStream(certFile); cert = X509Certificate.getInstance(inStream); } catch (CertificateException e) { throw new RuntimeException(e); } catch (FileNotFoundException e) { throw new RuntimeException(e); } cert.checkValidity(new Date()); return cert; } }

Amazon Q changing dependency from javax.security to java.security package and fixing compilation errors related to X509Certificate . It modified the code to get the X509Certificate from CertificateFactory instead of directly getting from the X509Certificate.getInstance.

import java.security.cert.*;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;
import java.util.Date; public class Security { public Certificate getCertificate(File certFile) throws CertificateExpiredException, CertificateNotYetValidException { X509Certificate cert = null; try { InputStream inStream = new FileInputStream(certFile); CertificateFactory cf = CertificateFactory.getInstance("X.509"); cert = (X509Certificate) cf.generateCertificate(inStream); } catch (CertificateException e) { throw new RuntimeException(e); } catch (FileNotFoundException e) { throw new RuntimeException(e); } cert.checkValidity(new Date()); return cert; } }

With Q Developer’s AI technology, it can automatically correct a wider range of issues that would otherwise require manual intervention, further streamlining the upgrade process and reducing the risk of costly delays or regressions.

Conclusion

Throughout this blog post, we explored the three major areas of improvement in the Amazon Q Developer agent for code transformation since its general availability: major version upgrades of popular frameworks, direct replacement of deprecated library calls, and leveraging our AI technology using Amazon Bedrock capabilities to correct compilation errors during Java 17 migration. By addressing these critical aspects, the Q Developer agent has become an even more powerful tool for organizations seeking to unlock the benefits of Java 17 while minimizing the time and effort required for application upgrades. As we continue to enhance the Q Developer agent based on customer feedback, we encourage you to explore the open source example application provided and experience firsthand how this tool can streamline your Java modernization journey. See Getting Started with Amazon Q Developer agent for code transformation for a step by step process to transforming a java application with Q Developer.

About the authors

Jonathan Vogel

Jonathan is a Developer Advocate at AWS. He was a DevOps Specialist Solutions Architect at AWS for two years prior to taking on the Developer Advocate role. Prior to AWS, he practiced professional software development for over a decade. Jonathan enjoys music, birding and climbing rocks.

 

 

 

Venugopalan Vasudevan

Venugopalan is a Senior Specialist Solutions Architect at Amazon Web Services (AWS), where he specializes in AWS Generative AI services. His expertise lies in helping customers leverage cutting-edge services like Amazon Q, and Amazon Bedrock to streamline development processes, accelerate innovation, and drive digital transformation.