Update RamUsage to better suit the 5 minute time specified

BauSystem_Main/src/de/steamwar/bausystem/features/world/AutoShutdownListener.java

@@ -79,5 +79,6 @@ public class AutoShutdownListener implements Listener {
                 }
             }, 20, 20);
         }
+        System.out.println("LEAVE");
     }
 }

BauSystem_Main/src/de/steamwar/bausystem/features/world/RamUsage.java

@@ -20,23 +20,30 @@
 package de.steamwar.bausystem.features.world;
 
 import lombok.experimental.UtilityClass;
-import org.bukkit.Bukkit;
 
-import java.lang.management.ManagementFactory;
-import java.util.logging.Level;
+import java.io.*;
 
 @UtilityClass
 public class RamUsage {
 
+    private File meminfo = new File("/proc/meminfo");
+
     public static double getUsage() {
-        try {
-            long memorySize = ((com.sun.management.OperatingSystemMXBean) ManagementFactory.getOperatingSystemMXBean()).getTotalPhysicalMemorySize();
-            long freeMemory = ((com.sun.management.OperatingSystemMXBean) ManagementFactory.getOperatingSystemMXBean()).getFreePhysicalMemorySize();
-            return (memorySize - freeMemory) / (double) memorySize;
-        } catch (Throwable throwable) {
-            Bukkit.getLogger().log(Level.WARNING, throwable.getMessage(), throwable);
+        try (BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(new FileInputStream(meminfo)))) {
+            String memTotal = bufferedReader.readLine().replaceAll(" +", " ");
+            bufferedReader.readLine();
+            String memAvailable = bufferedReader.readLine().replaceAll(" +", " ");
+
+            long memTotalLong = getNumber(memTotal);
+            long memAvailableLong = getNumber(memAvailable);
+            return (memTotalLong - memAvailableLong) / (double) memTotalLong;
+        } catch (IOException e) {
             return 1D;
         }
     }
 
+    private static long getNumber(String s) {
+        return Long.parseLong(s.split(" ")[1]);
+    }
+
 }