java -jar ysoserial-0.0.4-all.jar CommonsCollections1 "calc.exe" > payload.ser
ysoserial-0.0.4-all.jar is a legacy version of , a well-known proof-of-concept tool used by security researchers to generate payloads that exploit unsafe Java object deserialization. Overview of Ysoserial ysoserial-0.0.4-all.jar download