Usage of serialVersionUID in custom servlets which extends SlingSafeMethodsServlet

[cquser1]

Hi All,

I have seen in multiple instances wherein serialVersionUID is assigned some random Long value in custom servlet. I am not sure as to why exactly is this used. Don't see this variable getting used anywhere.

Can someone please let me know as to what purpose does it serve.

[daniel_henriqu1]

Hi.

serialVersionUID is a Java "thing" for Serializable classes: Stream Unique Identifiers.
It's used by the regular Java serialization mechanism: Serializable Objects.

Regarding the "random" long value, it has probably been generated/assigned by an IDE (Eclipse, IntelliJ), based on the characteristics of the corresponding class.

Some additional references about Servlets and serialization:

• Why does HttpServlet implement Serializable?
• Why do GenericServlet and HttpServlet implement the Serializable interface?

Best regards,

Daniel.

[smacdonald2008]

See -- http://stackoverflow.com/questions/285793/what-is-a-serialversionuid-and-why-should-i-use-it

[daniel_henriqu1 · Accepted solution]

Hi,

serialVersionUID is a Java "thing" for Serializable classes: Stream Unique Identifiers.
It's used by the regular Java serialization mechanism: Serializable Objects.

Regarding the "random" long value it has probably been generated/assigned by an IDE (Eclipse, IntelliJ), based on the characteristics of the corresponding class.

Some additional references about Servlets and serialization:

1. Why does HttpServlet implement Serializable?
2. Why do GenericServlet and HttpServlet implement the Serializable interface?

Best regards,

Daniel.

[smacdonald2008]

See this thread -- http://stackoverflow.com/questions/285793/what-is-a-serialversionuid-and-why-should-i-use-it

[cquser1]

Thanks a lot Scott and Daniel for your replies.