Dynamic Class Data Sharing not using the archive file-CodePudding

We are trying to use Dynamic Class Data Sharing (Dynamic CDS) with our spring boot application.

Created the CDS archive using the following command

java -Xlog:cds -XX:DumpLoadedClassList=cds.jsa -jar app-0.0.1-SNAPSHOT.jar

And trying to use the archive using the following command

java -Xlog:cds -XX:SharedArchiveFile=cds.jsa -jar app-0.0.1-SNAPSHOT.jar

But getting the following error in the beginning of the application startup

[0.009s][info][cds] trying to map cds.jsa
[0.009s][info][cds] Opened archive cds.jsa.
[0.009s][info][cds] _magic expected: 0xf00baba2
[0.009s][info][cds]          actual: 0x4f4e2023
[0.009s][info][cds] UseSharedSpaces: The shared archive file has a bad magic number.
[0.009s][info][cds] UseSharedSpaces: Unable to map shared spaces

openjdk version "17" 2021-09-14 (build 17 35-2724) Springboot 2.6.3

CodePudding user response：

The option --XX:DumpLoadedClassList=cds.jsa does not create a CDS archive - it is one step in creating a static CDS Archive File.

To create a Dynamic CDS Archive file you must use

java -Xlog:cds -XX:ArchiveClassesAtExit=cds.jsa -jar app-0.0.1-SNAPSHOT.jar

Source: https://docs.oracle.com/en/java/javase/17/docs/specs/man/java.html#creating-cds-archives