关于spring-core-5.2.8.RELEASE-sources包相较于对应jar包存在类缺失问题的技术问询

Hey there, let's break down why you're running into this issue with org.springframework:spring-core jars and their corresponding sources packages.

Why classes like org.springframework.cglib.proxy.MethodInterceptor aren’t in spring-core-sources #

• Spring repackages third-party libraries (such as CGLIB) into its own jars during the build process. This is a deliberate choice to avoid classpath conflicts—by moving these classes into Spring’s own namespace (like org.springframework.cglib instead of the original net.sf.cglib), Spring prevents clashes with other versions of CGLIB your project might depend on.
• These repackaged classes aren’t part of Spring’s native source code, so they won’t be included in spring-core-*-sources.jar files. The MethodInterceptor you’re looking for is actually a CGLIB library class, just relocated to Spring’s package structure.

How to get the source code for these classes #

• You can grab the original source directly from the CGLIB project. To find the exact CGLIB version Spring uses, check the pom.xml of the spring-core artifact you’re working with, or use your IDE’s dependency analysis tool.
• Most modern IDEs (IntelliJ IDEA, Eclipse, etc.) will automatically detect these repackaged classes and prompt you to download matching CGLIB sources when you try to view them, making this process straightforward.

This issue isn’t limited to 5.2.8.RELEASE #

• You’re spot on—this repackaging approach is a standard practice across multiple Spring versions (not just 5.2.8.RELEASE). Many 5.x series versions (and even older ones) use this method to manage third-party dependencies safely, so you’ll likely see the same behavior with other Spring core releases.

内容的提问来源于stack exchange，提问作者Michael