feat(statsig)!: Migrate to Java Core #1656

liran2000 · 2025-11-23T08:11:46Z

Migrated to Java Core according to Migration guide.

solves #1627.

@lindner and others you are welcome to review

Signed-off-by: liran2000 <[email protected]>

gemini-code-assist · 2025-11-23T08:12:09Z

Summary of Changes

Hello @liran2000, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request focuses on a significant upgrade of the Statsig Java SDK within the OpenFeature provider, transitioning from the legacy serversdk to the modern javacore library. This migration involves comprehensive updates to dependencies, adaptation to new API patterns for SDK initialization and feature evaluation, and refinement of the data structures used to represent Statsig configurations. The changes ensure the provider remains compatible with the latest Statsig Java offerings and enhances its interaction with the underlying SDK.

Highlights

Dependency Migration: The Statsig Java SDK dependency has been migrated from com.statsig:serversdk to com.statsig:javacore, updating the project to use the latest core library.
API Adaptation: The integration with Statsig has been updated to align with the new javacore API, including changes to Statsig initialization (now instance-based instead of static calls) and how feature gates, dynamic configs, and layers are fetched and evaluated.
StatsigUser Builder Pattern: The creation of StatsigUser objects now utilizes a builder pattern, reflecting changes in the javacore library's design.
Object Structure Simplification: The representation of DynamicConfig and Layer objects within the OpenFeature context has been simplified, removing fields like groupName and secondaryExposures that are handled differently or no longer directly exposed by the new SDK.
Test Suite Updates: Existing test cases have been modified to accommodate the new API and object structures, including adjustments to mocking behavior and assertion logic.

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Code Review

This pull request successfully migrates the Statsig provider to the new Java Core SDK. The changes are comprehensive, updating the provider logic, configuration, and tests to align with the new API, such as using builders, handling async operations with CompletableFuture, and using a non-static SDK instance. The tests have been notably improved by using mocking for SDK classes. My review includes suggestions to remove leftover debugging statements and commented-out code, fix a minor typo in the README, and enhance a test case for better robustness.

gemini-code-assist · 2025-11-23T08:13:25Z

providers/statsig/README.md

+## Release Notes

+### 0.3.0
+ Migrated to according to [Migration guide](https://docs.statsig.com/server-core/migration-guides/java#java-migration-steps).


There's a minor grammatical error in the release notes. It should be "Migrated according to..." instead of "Migrated to according to...".

Suggested change

Migrated to according to [Migration guide](https://docs.statsig.com/server-core/migration-guides/java#java-migration-steps).

Migrated according to [Migration guide](https://docs.statsig.com/server-core/migration-guides/java#java-migration-steps).

gemini-code-assist · 2025-11-23T08:13:25Z

providers/statsig/src/main/java/dev/openfeature/contrib/providers/statsig/StatsigProvider.java

+//            if (!assumeFailure(featureGate)) {
+//                evaluatedValue = featureGate.getValue();
+//            }


This commented-out code is no longer necessary with the new Statsig SDK and should be removed to improve code clarity.

providers/statsig/src/main/java/dev/openfeature/contrib/providers/statsig/StatsigProvider.java

...ers/statsig/src/test/java/dev/openfeature/contrib/providers/statsig/StatsigProviderTest.java

Signed-off-by: liran2000 <[email protected]>

lindner

Overall LGTM, just some minor nits, since I'm starting with JavaCore. Others who are already using this provider may have issues if the transitive deps have changed significantly.

lindner · 2025-11-25T00:43:54Z

...ers/statsig/src/test/java/dev/openfeature/contrib/providers/statsig/StatsigProviderTest.java

-        StatsigOptions statsigOptions = new StatsigOptions();
-        statsigOptions.setLocalMode(true);
+        StatsigOptions statsigOptions = new StatsigOptions.Builder()
+                //                .setLocalMode(true)


Remove? Or make it such that the test passes with/without?

lindner · 2025-11-25T00:45:57Z

providers/statsig/pom.xml

-            <version>1.18.1</version>
+            <artifactId>javacore</artifactId>
+            <version>0.12.1</version>
+            <classifier>uber</classifier>


Why is this uber? Does this include all of the transitive compiled versions for various platforms?

From docs:

The uber JAR is recommended for most use cases as it includes native libraries for all popular platforms and simplifies deployment. Use platform-specific JARs only if you need to minimize JAR size or have specific dependency requirements.

Recommended: Using the Uber JAR (All-in-One)
Since version 0.4.0, Statsig provides an “uber” JAR that contains both the core library and native libraries for popular supported platforms in a single package. This is the recommended approach for most users.

Since we are like a library here for multi-platform, this includes all, and consumers can control it more precisely if wanted.

lindner · 2025-11-25T00:46:44Z

providers/statsig/README.md

+## Release Notes

+### 0.3.0
+ Migrated to Java Core according to [Migration guide](https://docs.statsig.com/server-core/migration-guides/java#java-migration-steps).


Definitely mention that this is a major breaking change and that there is migration needed. Also mention that the last version of non-javacore requires a downgrade.

marked as a breaking change at the PR title for release notes and added this to the readme:

The provider usage is basically unchanged, the underlying implementation is changed.
As the initialization code may change, can refer to the migration guide for details.

lindner · 2025-11-25T00:48:39Z

providers/statsig/src/main/java/dev/openfeature/contrib/providers/statsig/StatsigProvider.java

        mutableContext.add("name", dynamicConfig.getName());
        mutableContext.add("value", Structure.mapToStructure(dynamicConfig.getValue()));
        mutableContext.add("ruleID", dynamicConfig.getRuleID());
-        mutableContext.add("groupName", dynamicConfig.getGroupName());


are these provided in a different way? If so document in the README.md

lindner · 2025-11-25T01:08:31Z

providers/statsig/src/main/java/dev/openfeature/contrib/providers/statsig/StatsigProvider.java

-        log.info("shutdown");
-        Statsig.shutdown();
+        log.info("shutdown begin");
+        CompletableFuture<Void> shutdownFuture = statsig.shutdown();


check if statsig != null?

Signed-off-by: liran2000 <[email protected]>

0.3.0

6039699

Signed-off-by: liran2000 <[email protected]>

liran2000 requested a review from a team as a code owner November 23, 2025 08:11

github-actions bot assigned liran2000 Nov 23, 2025

gemini-code-assist bot reviewed Nov 23, 2025

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0.3.0

5487253

Signed-off-by: liran2000 <[email protected]>

lindner approved these changes Nov 25, 2025

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lindner reviewed Nov 25, 2025

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liran2000 changed the title ~~feat(statsig): Migrate to Java Core~~ feat(statsig)!: Migrate to Java Core Nov 25, 2025

updates

104c062

Signed-off-by: liran2000 <[email protected]>

liran2000 requested a review from lindner November 25, 2025 06:18

updates

eef8493

Signed-off-by: liran2000 <[email protected]>

	Migrated to according to [Migration guide](https://docs.statsig.com/server-core/migration-guides/java#java-migration-steps).
	Migrated according to [Migration guide](https://docs.statsig.com/server-core/migration-guides/java#java-migration-steps).

feat(statsig)!: Migrate to Java Core #1656

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feat(statsig)!: Migrate to Java Core #1656

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liran2000 commented Nov 23, 2025 •

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