How do I monitor the computer s CPU memory and disk usage in Java

Question

I would like to monitor the following system information in Java    Current CPU usage    percent  Available memory   free total  Available disk space  free total    Note that I mean overall memory available to the whole system  not just the JVM    I m looking for a cross-platform solution  Linux  Mac  and Windows  that doesn t rely on my own code calling external programs or using JNI  Although these are viable options  I would prefer not to maintain OS-specific code myself if someone already has a better solution   If there s a free library out there that does this in a reliable  cross-platform manner  that would be great  even if it makes external calls or uses native code itself    Any suggestions are much appreciated   To clarify  I would like to get the current CPU usage for the whole system  not just the Java process es    The SIGAR API provides all the functionality I m looking for in one package  so it s the best answer to my question so far  However  due it being licensed under the GPL  I cannot use it for my original purpose  a closed source  commercial product   It s possible that Hyperic may license SIGAR for commercial use  but I haven t looked into it  For my GPL projects  I will definitely consider SIGAR in the future   For my current needs  I m leaning towards the following    For CPU usage  OperatingSystemMXBean getSystemLoadAverage     OperatingSystemMXBean getAvailableProcessors    load average per cpu  For memory  OperatingSystemMXBean getTotalPhysicalMemorySize   and OperatingSystemMXBean getFreePhysicalMemorySize   For disk space  File getTotalSpace   and File getUsableSpace     Limitations   The getSystemLoadAverage   and disk space querying methods are only available under Java 6  Also  some JMX functionality may not be available to all platforms  i e  it s been reported that getSystemLoadAverage   returns -1 on Windows    Although originally licensed under GPL  it has been changed to Apache 2 0  which can generally be used for closed source  commercial products

User · Answer

Have a look at this very detailled article: http://nadeausoftware.com/articles/2008/03/java_tip_how_get_cpu_and_user_time_benchmarking#UsingaSuninternalclasstogetJVMCPUtime

To get the percentage of CPU used, all you need is some simple maths:

MBeanServerConnection mbsc = ManagementFactory.getPlatformMBeanServer();

OperatingSystemMXBean osMBean = ManagementFactory.newPlatformMXBeanProxy(
mbsc, ManagementFactory.OPERATING_SYSTEM_MXBEAN_NAME, OperatingSystemMXBean.class);

long nanoBefore = System.nanoTime();
long cpuBefore = osMBean.getProcessCpuTime();

// Call an expensive task, or sleep if you are monitoring a remote process

long cpuAfter = osMBean.getProcessCpuTime();
long nanoAfter = System.nanoTime();

long percent;
if (nanoAfter > nanoBefore)
 percent = ((cpuAfter-cpuBefore)*100L)/
   (nanoAfter-nanoBefore);
else percent = 0;

System.out.println("Cpu usage: "+percent+"%");

Note: You must import com.sun.management.OperatingSystemMXBean and not java.lang.management.OperatingSystemMXBean.

User · Answer

This works for me perfectly without any external API  just native Java hidden feature     import com sun management OperatingSystemMXBean      OperatingSystemMXBean osBean   ManagementFactory getPlatformMXBean                  OperatingSystemMXBean class      What   CPU load this current JVM is taking  from 0 0-1 0 System out println osBean getProcessCpuLoad         What   load the overall system is at  from 0 0-1 0 System out println osBean getSystemCpuLoad

User · Answer

The accepted answer in 2008 recommended SIGAR  However  as a comment from 2014   Alvaro  says      Be careful when using Sigar  there are problems on x64 machines      Sigar 1 6 4 is crashing  EXCEPTION ACCESS VIOLATION and it seems the library   doesn t get updated since 2010   My recommendation is to use https   github com oshi oshi  Or the answer mentioned above

User · Answer

For disk space  if you have Java 6  you can use the getTotalSpace and getFreeSpace methods on File  If you re not on Java 6  I believe you can use Apache Commons IO to get some of the way there   I don t know of any cross platform way to get CPU usage or Memory usage I m afraid

User · Answer

A lot of this is already available via JMX   With Java 5  JMX is built-in and they include a JMX console viewer with the JDK   You can use JMX to monitor manually  or invoke JMX commands from Java if you need this information in your own run-time

User · Answer

YOU CAN TRY THIS TOO     import java io File   import java lang management ManagementFactory     import java lang management OperatingSystemMXBean   import java lang reflect Method   import java lang reflect Modifier   import java lang management RuntimeMXBean   import java io     import java net     import java util     import java io LineNumberReader   import java lang management ManagementFactory  import com sun management OperatingSystemMXBean  import java lang management ManagementFactory  import java util Random      public class Pragati          public static void printUsage Runtime runtime              long total  free  used       int mb   1024 1024        total   runtime totalMemory         free   runtime freeMemory         used   total - free       System out println   nTotal Memory      total   mb    MB         System out println   Memory Used      used   mb    MB         System out println   Memory Free      free   mb    MB         System out println  Percent Used        double used  double total  100              System out println  Percent Free        double free  double total  100                   public static void log Object message                         System out println message                       public static int calcCPU long cpuStartTime  long elapsedStartTime  int cpuCount                         long end   System nanoTime                 long totalAvailCPUTime   cpuCount    end-elapsedStartTime                long totalUsedCPUTime   ManagementFactory getThreadMXBean   getCurrentThreadCpuTime  -cpuStartTime                 log  Total CPU Time     totalUsedCPUTime     ns                    log  Total Avail CPU Time     totalAvailCPUTime     ns                  float per     float totalUsedCPUTime 100   float totalAvailCPUTime               log  per                return  int per                     static boolean isPrime int n                    2 is the smallest prime             if  n  lt   2                                return n    2                        even numbers other than 2 are not prime             if  n   2    0                                return false                        check odd divisors from 3         to the square root of n          for  int i   3  end    int Math sqrt n   i  lt   end  i    2                         if  n   i    0                      return false                       return true        public static void main String    args                    int mb   1024 1024              int gb   1024 1024 1024                  PHYSICAL MEMORY USAGE                 System out println   n     Sizes in Mega Bytes      n                com sun management OperatingSystemMXBean operatingSystemMXBean    com sun management OperatingSystemMXBean ManagementFactory getOperatingSystemMXBean                  RuntimeMXBean runtimeMXBean   ManagementFactory getRuntimeMXBean                  operatingSystemMXBean    com sun management OperatingSystemMXBean  ManagementFactory getOperatingSystemMXBean                com sun management OperatingSystemMXBean os    com sun management OperatingSystemMXBean              java lang management ManagementFactory getOperatingSystemMXBean                long physicalMemorySize   os getTotalPhysicalMemorySize                System out println  PHYSICAL MEMORY DETAILS  n                System out println  total physical memory       physicalMemorySize   mb    MB                 long physicalfreeMemorySize   os getFreePhysicalMemorySize                System out println  total free physical memory       physicalfreeMemorySize   mb    MB                   DISC SPACE DETAILS                File diskPartition   new File  C                 File diskPartition1   new File  D                 File diskPartition2   new File  E                 long totalCapacity   diskPartition getTotalSpace     gb              long totalCapacity1   diskPartition1 getTotalSpace     gb              double freePartitionSpace   diskPartition getFreeSpace     gb              double freePartitionSpace1   diskPartition1 getFreeSpace     gb              double freePartitionSpace2   diskPartition2 getFreeSpace     gb              double usablePatitionSpace   diskPartition getUsableSpace     gb              System out println   n     Sizes in Giga Bytes      n                System out println  DISC SPACE DETAILS  n                  System out println  Total C partition size       totalCapacity    GB                  System out println  Usable Space       usablePatitionSpace    GB                System out println  Free Space in drive C        freePartitionSpace    GB                System out println  Free Space in drive D         freePartitionSpace1    GB                System out println  Free Space in drive E      freePartitionSpace2    GB                if freePartitionSpace  lt   totalCapacity 10    freePartitionSpace1  lt   totalCapacity1 10                                System out println      alert                                  else                 System out println  no alert                 Runtime runtime              byte   bytes              System out println   n  n  MEMORY DETAILS      n                   Print initial memory usage              runtime   Runtime getRuntime                printUsage runtime                   Allocate a 1 Megabyte and print memory usage             bytes   new byte 1024 1024               printUsage runtime                bytes   null                 Invoke garbage collector to reclaim the allocated memory              runtime gc                    Wait 5 seconds to give garbage collector a chance to run             try               Thread sleep 5000                 catch InterruptedException e                e printStackTrace                return                                Total memory will probably be the same as the second printUsage call                 but the free memory should be about 1 Megabyte larger if garbage                collection kicked in              printUsage runtime               for int i   0  i  lt  30  i                                                    long start   System nanoTime                               log start                             number of available processors                           int cpuCount   ManagementFactory getOperatingSystemMXBean   getAvailableProcessors                             Random random   new Random start                            int seed   Math abs random nextInt                              log   n  n CPU USAGE DETAILS  n n                             log  Starting Test with     cpuCount     CPUs and random number     seed                            int primes   10000                                                       long startCPUTime   ManagementFactory getThreadMXBean   getCurrentThreadCpuTime                             start   System nanoTime                             while primes    0                                                         if isPrime seed                                                                 primes--                                                            seed                                                        float cpuPercent   calcCPU startCPUTime  start  cpuCount                            log  CPU USAGE       cpuPercent                                      try                                                         Thread sleep 1000                                                       catch  InterruptedException e                            try                               Thread sleep 500                 enter code here              catch  Exception ignored

User · Answer

Along the lines of what I mentioned in this post  I recommend you use the SIGAR API   I use the SIGAR API in one of my own applications and it is great   You ll find it is stable  well supported  and full of useful examples   It is open-source with a GPL 2 Apache 2 0 license   Check it out   I have a feeling it will meet your needs   Using Java and the Sigar API you can get Memory  CPU  Disk  Load-Average  Network Interface info and metrics  Process Table information  Route info  etc

User · Answer

In JDK 1 7  you can get system CPU and memory usage via com sun management OperatingSystemMXBean   This is different than java lang management OperatingSystemMXBean   long    getCommittedVirtualMemorySize   Returns the amount of virtual memory that is guaranteed to be available to the running process in bytes  or -1 if this operation is not supported   long    getFreePhysicalMemorySize   Returns the amount of free physical memory in bytes   long    getFreeSwapSpaceSize   Returns the amount of free swap space in bytes   double  getProcessCpuLoad   Returns the  recent cpu usage  for the Java Virtual Machine process   long    getProcessCpuTime   Returns the CPU time used by the process on which the Java virtual machine is running in nanoseconds   double  getSystemCpuLoad   Returns the  recent cpu usage  for the whole system   long    getTotalPhysicalMemorySize   Returns the total amount of physical memory in bytes   long    getTotalSwapSpaceSize   Returns the total amount of swap space in bytes

User · Answer

The following code is Linux  maybe Unix  only  but it works in a real project       private double getAverageValueByLinux   throws InterruptedException       try            long delay   50          List lt Double gt  listValues   new ArrayList lt Double gt             for  int i   0  i  lt  100  i                  long cput1   getCpuT                Thread sleep delay               long cput2   getCpuT                double cpuproc    1000d    cput2 - cput1      double  delay              listValues add cpuproc                     listValues remove 0           listValues remove listValues size   - 1           double sum   0 0          for  Double double1   listValues                sum    double1                    return sum   listValues size          catch  Exception e            e printStackTrace            return 0            private long getCpuT throws FileNotFoundException  IOException       BufferedReader reader   new BufferedReader new FileReader   proc stat         String line   reader readLine        Pattern pattern   Pattern compile    D    d    D    d    D    d    D    d         Matcher m   pattern matcher line        long cpuUser   0      long cpuSystem   0      if  m find              cpuUser   Long parseLong m group 1            cpuSystem   Long parseLong m group 3              return cpuUser   cpuSystem

User · Answer

Make a batch file  Pc bat  as  typeperf -sc 1   mukit processor  Total     Processor Time   You can use the class MProcess         Md  Mukit Hasan   CSE-JU 35      import java io     public class MProcessor    public MProcessor         String s      try           Process ps   Runtime getRuntime   exec  Pc bat            BufferedReader br   new BufferedReader new InputStreamReader ps getInputStream              while  s   br readLine       null                System out println s                       catch  Exception ex             System out println ex toString                   Then after some string manipulation  you get the CPU use  You can use the same process for other tasks   --Mukit Hasan

User · Answer

The following supposedly gets you CPU and RAM  See ManagementFactory for more details   import java lang management ManagementFactory  import java lang management OperatingSystemMXBean  import java lang reflect Method  import java lang reflect Modifier   private static void printUsage       OperatingSystemMXBean operatingSystemMXBean   ManagementFactory getOperatingSystemMXBean      for  Method method   operatingSystemMXBean getClass   getDeclaredMethods          method setAccessible true       if  method getName   startsWith  get            amp  amp  Modifier isPublic method getModifiers                   Object value          try               value   method invoke operatingSystemMXBean             catch  Exception e                value   e               try         System out println method getName             value            if        for

[java] How do I monitor the computer's CPU, memory, and disk usage in Java?

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