diff --git a/src/main/java/mpo/dayon/common/log/LogAppender.java b/src/main/java/mpo/dayon/common/log/LogAppender.java
index e8a37ed7..cb41585e 100644
--- a/src/main/java/mpo/dayon/common/log/LogAppender.java
+++ b/src/main/java/mpo/dayon/common/log/LogAppender.java
@@ -1,17 +1,16 @@
 package mpo.dayon.common.log;
 
-import java.text.DateFormat;
 import java.text.SimpleDateFormat;
 import java.time.Instant;
 import java.util.Date;
 
 public abstract class LogAppender {
-	private final DateFormat dateFormat = new SimpleDateFormat("HH:mm:ss.SSS");
+	private static final SimpleDateFormat DATE_FORMAT = new SimpleDateFormat("HH:mm:ss.SSS");
 
 	protected String format(LogLevel level, String message) {
 		message = (message == null) ? "" : message;
 		return String.format("[%20.20s] [%5.5s] (%s) %s", Thread.currentThread().getName(), level,
-				dateFormat.format(Date.from(Instant.now())), message);
+				DATE_FORMAT.format(Date.from(Instant.now())), message);
 	}
 
 	public void append(LogLevel level, String message) {
diff --git a/src/main/java/mpo/dayon/common/monitoring/BigBrother.java b/src/main/java/mpo/dayon/common/monitoring/BigBrother.java
index 8b3250a0..e022a273 100644
--- a/src/main/java/mpo/dayon/common/monitoring/BigBrother.java
+++ b/src/main/java/mpo/dayon/common/monitoring/BigBrother.java
@@ -6,17 +6,20 @@
 import mpo.dayon.common.monitoring.counter.Counter;
 
 public final class BigBrother {
-    private static final BigBrother INSTANCE = new BigBrother();
-
-    private final Timer timer = new Timer("BigBrother");
 
     private BigBrother() {
     }
 
+    private static class Helper {
+        private static final BigBrother INSTANCE = new BigBrother();
+    }
+
     public static BigBrother get() {
-        return INSTANCE;
+        return Helper.INSTANCE;
     }
 
+    private final Timer timer = new Timer("BigBrother");
+
     /**
      * @param instantRatePeriod millis
      */
diff --git a/src/main/java/mpo/dayon/common/utils/SystemUtilities.java b/src/main/java/mpo/dayon/common/utils/SystemUtilities.java
index cf920d00..d20499ce 100644
--- a/src/main/java/mpo/dayon/common/utils/SystemUtilities.java
+++ b/src/main/java/mpo/dayon/common/utils/SystemUtilities.java
@@ -93,7 +93,7 @@ public static String getSystemPropertiesEx() {
     public static String getRamInfo() {
         final double freeMG = Runtime.getRuntime().freeMemory();
         final double totalMG = Runtime.getRuntime().totalMemory();
-        return UnitUtilities.toByteSize(totalMG - freeMG, false) + " of " + UnitUtilities.toByteSize(totalMG, false);
+        return format("%s of %s", UnitUtilities.toByteSize(totalMG - freeMG, false), UnitUtilities.toByteSize(totalMG, false));
     }
 
     public static void safeClose(Closeable... closeables) {