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What is a compile time constant in Java? What is the risk of using it?

Compile time constant and Risk

public static final variables are also known as a compile-time constant, the public is optional there. They are replaced with actual values at compile time because compiler know their value up-front and also knows that it cannot be changed during run-time.

Risk associate with Compile time constant

One of the problems with this is that if you happened to use a public static final variable from some in-house or third party
library and their value changed later than your client will still be using old value even after you deploy a new version of JARs. To avoid that, make sure you compile your program when you upgrade dependency JAR files.

Discussion (1)

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Ho Anh

Thank you. But I'm still wondering why Java doesn't allow runtime constant?