How to monitor available memory (including cache and cache) in Java?

I have searched for possible solutions, such as how to monitor the computer's CPU, memory, and disk usage in Java But the memory used in buffers and caches is not mentioned anywhere?

For example, on Linux, output free - M:

             total       used       free     shared    buffers     cached
Mem:          2011       1835        175          0        309        847
-/+ buffers/cache:        678       1333
Swap:         1998          0       1998

I have tested the output of sigar, which reports 175 MB of available memory

The reason for this problem is when the operating system has little memory? In the previous free - M output, 175mb seemed quite low; But by adding buffers and caches, it is clear that the available memory is actually 1333 MB of 2 GB

All in all, can you get a value of 1333 MB as the value of available memory using Java? As I have mentioned, so far, I only know how to get 175 MB value

Solution

If you are trying to get the memory statistics of the operating system itself (not the JVM), you can use JNA or JNI to map platform specific native API calls directly to the operating system