On what operating system, what version, what hardware, with how much memory, how many CPUs, how many cores, which version of Java, 32 or 64 bits, how many other processes already running, how many total threads already running, how much swap space available, what processor utilisation, ... ?
Are you getting the concept that this is not a meaningful question as it stands?
I guess, Max thread constraint can not be directly applied to JVM.
It is a setting, which comes with any middleware server.
In weblogic, we create work managers and specify Max thread constraints.