Java Threads
Internal
Subjects
Concepts
Daemon Thread
Java Threads and Linux Processes
On a Linux system, each JVM thread counts as a "process", in that it is subject to system-wide and user-wide process number limitations - see "maximum number of processes allowed on a system" and "maximum number of processes available to a single user". When a JVM instance adjust its number of threads, the change is reflected by /proc/stat "processes" count.
For an example of what happens when the number of Linux processes allowed to an user is reached, see
A simple Java program that allows experimenting with threads:
Java Thread Stack Memory Management
The default thread stack size on 64-bit systems is 1024K. 64k is the least amount of stack space allowed per thread.
It can be modified with with the -Xss option:
java ... -Xss<size> ...
where "<size>" represents the amount of memory and the measure unit (ex "2048k").
More about Java memory management can be found here