Read various information of a process.
This requires Linux, as it uses procfs.
As some data can't be accessed within Java, JNI had to be used.
That means a native library must be compiled. Within src/main/c/ the required sources and a compile script are present.
The resulting library (libpstats.so) must be present in java.library.path. Either use -Djava.library.path to point to a directory with libpstats.so in it, or put libpstats.so in a default directory (not recommended).
All memory sizes are in pages. Use SysConf.calculateMemorySize to convert to bytes.
All times are in ticks. To convert to seconds. Use SysConf.calculateSeconds to convert to seconds. Seconds are not full numbers.
As both of these are not really constant, JNI is used to get the correct value.