memorycalc.java

public class MemoryInfoComponent {
  private static final long MB = 1048576L;
  
  public static Map<String, String> getMemoryStats() throws Exception {
    Runtime rt = Runtime.getRuntime();
    MemoryMXBean mbean = ManagementFactory.getMemoryMXBean();
    long usedMemory = rt.totalMemory() - rt.freeMemory();
    Map<String, String> memoryStats = new HashMap<>();
    memoryStats.put("JVM total memory", (rt.totalMemory() / 1048576L) + " MB");
    memoryStats.put("JVM used memory", (usedMemory / 1048576L) + " MB");
    memoryStats.put("JVM free memory", (rt.freeMemory() / 1048576L) + " MB");
    memoryStats.put("Heap init size", (mbean.getHeapMemoryUsage().getInit() / 1048576L) + " MB");
    memoryStats.put("Heap max size", (mbean.getHeapMemoryUsage().getMax() / 1048576L) + " MB");
    memoryStats.put("Heap used size", (mbean.getHeapMemoryUsage().getUsed() / 1048576L) + " MB");
    memoryStats.put("Heap commited", (mbean.getHeapMemoryUsage().getCommitted() / 1048576L) + " MB");
    return memoryStats;
  }
}