Generated `__BeanFactoryRegistrations.java` file contains "too many constants" when building with many beans

[manasjoshi14]

Hi,

I’m running into a problem with a pretty big Spring project (about 18,000 beans). When I build with AOT processing turned on, the build crashes with:

/<_REDACTED_>/AotProcessingApplication__BeanFactoryRegistrations.java:18253: error: too many constants
public class AotProcessingApplication__BeanFactoryRegistrations {

(The generated file is massive—tens of thousands of lines.)

A couple extra details:

• The project has a huge number of Spring beans/configs.
• From what I can tell, the generated AotProcessingApplication__BeanFactoryRegistrations file is blowing past Java’s class constant pool limit.

I searched around and found #33126, which describes a similar situation, but that seemed to be hitting method size limits rather than constant pool limits.

Here’s my setup:

• Spring: 6.2.7
• Spring Boot: 3.5.0
• JDK: 21
• Build: Gradle

---

Is there any way to avoid hitting this limit? Can the generated BeanFactory registration file be split up, or is there a recommended workaround for big projects like this?
Right now I'm trying to break up the generated file using a Python script as a Gradle post-task, but it is pretty hacky.

Thanks a lot for any pointers!

[sbrannen]

Indeed, that is problematic.

I modified the applyToWithLargeBeanDefinitionsCreatesSlices() test in BeanRegistrationsAotContributionTests so that it attempts to process 18_000 beans, and that fails as follows.

org.springframework.core.test.tools.CompilationException: Unable to compile source


too many constants /com/example/TestTarget__BeanFactoryRegistrations.java 11:8

---- source:   com/example/TestTarget__BeanFactoryRegistrations.java

We'll have to see if we can expand on the strategy used in #33126.

Though, I suppose we might end up having to find a way to split the source file into multiple source files.