JVM hashcode function - Java

It depends on which VM you are using.
Assuming that you are using Oracle default JVM - which is HotSpot, then I can tell you that HotSpot has six hashCode() implementations. You can choose it using -XX:hashCode=n flag running JVM via command line, where n:
0 – Park-Miller RNG (default)
1 – f(address, global_statement)
2 – constant 1
3 – Serial counter
4 – Object address
5 – Thread-local Xorshift

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