Wrong emphasis. It must be read "flaw in open source Java software.
The problem is Java, not Open Source.
The problem is Java, not Open Source.
Nothing about Java or it's community makes it any more prone than most other languages to exposing deserialisation into arbitrary objects.
[0] https://github.com/mazen160/struts-pwn_CVE-2017-9805/blob/ma... [1] https://blog.nelhage.com/2011/03/exploiting-pickle/