Eclipse Code Changes Not Taking Effect

1. The code was not saved: it is possible that the changes made to the code were not saved, resulting in the original code still being used at runtime.
2. Compilation error: The modified code contains syntax or logical errors, resulting in a failed compilation and thus not functioning. The code needs to be checked and corrected.
3. Dependency issue: The modified code involves dependencies on libraries or modules, but the project was not rebuilt, resulting in the dependencies not being updated and the code modifications not taking effect. It is necessary to rebuild the project to update the dependencies.
4. Cache issue: It is possible that the cache in the IDE or build tool has not been cleared, causing the modified code to not be reloaded. You will need to clear the cache and recompile the project.
5. Environmental issue: The modified code is not taking effect in a specific environment, which may be due to configuration issues or incorrect environment variable settings. It is necessary to examine the configuration related to the environment and make adjustments.

Summary: If the changes made to the code are not taking effect, it is important to systematically check the possible reasons listed above and gradually fix the issue to ensure that the modified code works correctly.