Java瞬态关键词语法糖？

Question

Why wasn't transient solved by using annotations instead of introducing a keyword?

It seems like the transient keyword doesn't really provide any native functionality to the language, and seems to be more syntactic-sugar to prevent accidental serialization.

Am I missing something?

Answer 1

Java transient keyword was added from the first java version, while Annotations was added later in 1.5 version

Actually transient uses ad hoc annotation mechanism :

Java platform has always had various ad hoc annotation mechanisms. For example the transient modifier is an ad hoc annotation indicating that a field should be ignored by the serialization subsystem

Notice the Scala has @transient and also volatile:

@transient Marks a field to be non-persistent; this is equivalent to the transient modifier in Java.

@volatile Marks a field which can change its value outside the control of the program; this is equivalent to the volatile modifier in Java.

Answer 2

The transient keyword predates annotations as per the comment above. You could use AOP to create your own marker and hence annotate wherever you want to make class members transient although your markers would still be using the transient keyword in the background.