CSS System Monitor
A simple system monitor for tracking memory usage.
The displayed "max", "total" and "free" memory is obtained from the Java
Runtime API, and its meaning is not immediately obvious:
- "Max" Memory:
The maximum amount of memory that the Java Virtual Machine (JVM) will
ever attempt to use. It is an upper bound that prevents the JVM from using
all of the computer's memory.
- "Total":
The amount of memory that the JVM currently uses for objects in-use as well
as new objects. So this includes what most people would call "available"
memory, i.e. memory that the JVM has reserved for new objects but doesn't
currently use.
- "Free":
Memory that the JVM considers "free".
In simple terms of "available" and "used" memory
one can consider "max - total + free" the available memory,
but the behavior of the JVM's garbage collection is very unpredictable:
It will sometimes hold on to memory that was freed after closing some part
of the application, while at other times such memory shows up as free
right away.
Manual Garbage Collection
Pressing the "GC" button will trigger a garbage collection.
This could be useful for tests, but in general the garbage collection
mechanism is best left to the JVM, i.e. there is no need for end users
to periodically trigger a GC.
Setup
All the settings are adjusted via the System Monitor preference page.