java - What is shared in a JVM -


what 2 different java programs, running in 1 same java virtual machine, share together?

something comes mind, regarding singleton classes: can instantiated once per jvm. means if 2 different java programs use 1 same class, both accessing same instance of singleton class?

what other things shared?

if run java command multiple times, multiple instances of jvm. in theory these entirely separate nothing shared, implementations of jvm (now or in past) might attempt share portions of data.

i haven't looked @ recently, 10 years there version of sun jvm attempt "share" .class file images between jvm instances. (this supposedly useful on servers there might dozens of jvms running @ once , might come , go rapidly.)

i'm not recalling other data shared, there may have been more, or other data may have been added since. (though there isn't else can shared between jvms.)

but again, in theory should "transparent" , not affect operation of individual jvm instance.

there provision "warm started" jvms partially loaded prior final command. did require configuration on part of system admin, otherwise transparent.


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