Can We Modify Java Annotation Parameter Values at Runtime?

How to Modify Annotation Parameter Values at Runtime

Problem Statement

Consider a compiled class with an annotation defined as follows:

Without altering the source code, can we modify the value of "someProperty" at runtime to a different value, such that subsequent reflection will retrieve the updated value instead of the default?

Solution

Disclaimer: The solution may not be applicable on all platforms (e.g., macOS).

Approach:

Leveraging Java's annotation reflection mechanism, we can dynamically modify the underlying annotation values by manipulating its internal data structures.

Code:

Usage Example:

Advantages:

• No need to create a new annotation instance
• Does not require prior knowledge of the concrete annotation class
• Minimal side effects as it operates on the original annotation instance

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