apache/dubbo

[Bug] Compatibility issues when migrating from Dubbo 2.5.x to 3.3.x

Open

#16046 opened on Jan 24, 2026

View on GitHub
 (7 comments) (0 reactions) (0 assignees)Java (41,524 stars) (26,453 forks)batch import
help wanted

Description

Pre-check

  • I am sure that all the content I provide is in English.

Search before asking

  • I had searched in the issues and found no similar issues.

Apache Dubbo Component

Java SDK (apache/dubbo)

Dubbo Version

Dubbo 3.3.5, JDK 1.8, Linux

Steps to reproduce this issue

When migrating Dubbo2.5.x project up to 3.3.x, there are two issues found.

  1. If there are two registry defined, but their properties are all same except the Id of registry. This is ok with Dubbo 2.5.x, but the project cannot start with Dubbo 3.3.x.

  2. If there is dubbo:annoation in the xml config, the project cannot start with Dubbo 3.3.x

What you expected to happen

It should be smooth during migration up to 3.3.x.

Anything else

No response

Do you have a (mini) reproduction demo?

  • Yes, I have a minimal reproduction demo to help resolve this issue more effectively!

Are you willing to submit a pull request to fix on your own?

  • Yes I am willing to submit a pull request on my own!

Code of Conduct

Contributor guide

Tech stack
java
Domain
backend
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
JavaDubbo frameworkXML configuration
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40
Research direction
The issue describes two compatibility bugs when migrating from Dubbo 2.5.x to 3.3.x. First, duplicate registries with identical properties except ID cause startup failure; investigate how Dubbo 3.3.x validates registry definitions, possibly in RegistryConfig or related XML parsing. Second, dubbo:annotation in XML fails; check how annotations are processed in the new version. Look at the Dubbo source code (e.g., org.apache.dubbo.config.spring.beans.factory.annotation) and XML schema parsing (spring.schemas, etc.). Also review existing tests for migration scenarios.