How do I check CPU and Memory Usage in Java?

Question

I need to check CPU and memory usage for the server in java, anyone know how it could be done?

Answer 1

If you are looking specifically for memory in JVM:

Runtime runtime = Runtime.getRuntime();  NumberFormat format = NumberFormat.getInstance();  StringBuilder sb = new StringBuilder(); long maxMemory = runtime.maxMemory(); long allocatedMemory = runtime.totalMemory(); long freeMemory = runtime.freeMemory();  sb.append("free memory: " + format.format(freeMemory / 1024) + "<br/>"); sb.append("allocated memory: " + format.format(allocatedMemory / 1024) + "<br/>"); sb.append("max memory: " + format.format(maxMemory / 1024) + "<br/>"); sb.append("total free memory: " + format.format((freeMemory + (maxMemory - allocatedMemory)) / 1024) + "<br/>"); 

However, these should be taken only as an estimate...

Answer 2

import java.io.File; import java.text.NumberFormat;  public class SystemInfo {      private Runtime runtime = Runtime.getRuntime();      public String info() {         StringBuilder sb = new StringBuilder();         sb.append(this.osInfo());         sb.append(this.memInfo());         sb.append(this.diskInfo());         return sb.toString();     }      public String osName() {         return System.getProperty("os.name");     }      public String osVersion() {         return System.getProperty("os.version");     }      public String osArch() {         return System.getProperty("os.arch");     }      public long totalMem() {         return Runtime.getRuntime().totalMemory();     }      public long usedMem() {         return Runtime.getRuntime().totalMemory() - Runtime.getRuntime().freeMemory();     }      public String memInfo() {         NumberFormat format = NumberFormat.getInstance();         StringBuilder sb = new StringBuilder();         long maxMemory = runtime.maxMemory();         long allocatedMemory = runtime.totalMemory();         long freeMemory = runtime.freeMemory();         sb.append("Free memory: ");         sb.append(format.format(freeMemory / 1024));         sb.append("<br/>");         sb.append("Allocated memory: ");         sb.append(format.format(allocatedMemory / 1024));         sb.append("<br/>");         sb.append("Max memory: ");         sb.append(format.format(maxMemory / 1024));         sb.append("<br/>");         sb.append("Total free memory: ");         sb.append(format.format((freeMemory + (maxMemory - allocatedMemory)) / 1024));         sb.append("<br/>");         return sb.toString();      }      public String osInfo() {         StringBuilder sb = new StringBuilder();         sb.append("OS: ");         sb.append(this.osName());         sb.append("<br/>");         sb.append("Version: ");         sb.append(this.osVersion());         sb.append("<br/>");         sb.append(": ");         sb.append(this.osArch());         sb.append("<br/>");         sb.append("Available processors (cores): ");         sb.append(runtime.availableProcessors());         sb.append("<br/>");         return sb.toString();     }      public String diskInfo() {         /* Get a list of all filesystem roots on this system */         File[] roots = File.listRoots();         StringBuilder sb = new StringBuilder();          /* For each filesystem root, print some info */         for (File root : roots) {             sb.append("File system root: ");             sb.append(root.getAbsolutePath());             sb.append("<br/>");             sb.append("Total space (bytes): ");             sb.append(root.getTotalSpace());             sb.append("<br/>");             sb.append("Free space (bytes): ");             sb.append(root.getFreeSpace());             sb.append("<br/>");             sb.append("Usable space (bytes): ");             sb.append(root.getUsableSpace());             sb.append("<br/>");         }         return sb.toString();     } }