diff --git a/src/main/java/org/apache/commons/logging/LogFactory.java b/src/main/java/org/apache/commons/logging/LogFactory.java
index be9acd0..2d8eb08 100644
--- a/src/main/java/org/apache/commons/logging/LogFactory.java
+++ b/src/main/java/org/apache/commons/logging/LogFactory.java
@@ -133,7 +133,7 @@ public abstract class LogFactory {
      * generated by LogFactory or LogFactoryImpl. When non-null,
      * interesting events will be written to the specified object.
      */
-    private static PrintStream diagnosticsStream;
+    private static final PrintStream DIAGNOSTICS_STREAM;
 
     /**
      * A string that gets prefixed to every message output by the
@@ -1088,7 +1088,7 @@ public abstract class LogFactory {
                         // has been specified. Several well known containers use this mechanism to adapt JCL
                         // to their native logging system.
                         //
-                        final StringBuffer msg = new StringBuffer();
+                        final StringBuilder msg = new StringBuilder();
                         msg.append("The application has specified that a custom LogFactory implementation ");
                         msg.append("should be used but Class '");
                         msg.append(factoryClass);
@@ -1503,7 +1503,7 @@ public abstract class LogFactory {
      * @since 1.1
      */
     protected static boolean isDiagnosticsEnabled() {
-        return diagnosticsStream != null;
+        return DIAGNOSTICS_STREAM != null;
     }
 
     /**
@@ -1525,10 +1525,10 @@ public abstract class LogFactory {
      * @param msg is the diagnostic message to be output.
      */
     private static final void logDiagnostic(final String msg) {
-        if (diagnosticsStream != null) {
-            diagnosticsStream.print(diagnosticPrefix);
-            diagnosticsStream.println(msg);
-            diagnosticsStream.flush();
+        if (DIAGNOSTICS_STREAM != null) {
+            DIAGNOSTICS_STREAM.print(diagnosticPrefix);
+            DIAGNOSTICS_STREAM.println(msg);
+            DIAGNOSTICS_STREAM.flush();
         }
     }
 
@@ -1539,9 +1539,9 @@ public abstract class LogFactory {
      * @since 1.1
      */
     protected static final void logRawDiagnostic(final String msg) {
-        if (diagnosticsStream != null) {
-            diagnosticsStream.println(msg);
-            diagnosticsStream.flush();
+        if (DIAGNOSTICS_STREAM != null) {
+            DIAGNOSTICS_STREAM.println(msg);
+            DIAGNOSTICS_STREAM.flush();
         }
     }
 
@@ -1616,7 +1616,7 @@ public abstract class LogFactory {
             return;
         }
         if (classLoader != null) {
-            final StringBuffer buf = new StringBuffer(prefix + "ClassLoader tree:");
+            final StringBuilder buf = new StringBuilder(prefix + "ClassLoader tree:");
             for(;;) {
                 buf.append(objectId(classLoader));
                 if (classLoader == systemClassLoader) {
@@ -1704,7 +1704,7 @@ public abstract class LogFactory {
             classLoaderName = "UNKNOWN";
         }
         diagnosticPrefix = "[LogFactory from " + classLoaderName + "] ";
-        diagnosticsStream = initDiagnostics();
+        DIAGNOSTICS_STREAM = initDiagnostics();
         logClassLoaderEnvironment(LogFactory.class);
         factories = createFactoryStore();
         if (isDiagnosticsEnabled()) {
diff --git a/src/main/java/org/apache/commons/logging/LogSource.java b/src/main/java/org/apache/commons/logging/LogSource.java
index 60f733a..baacded 100644
--- a/src/main/java/org/apache/commons/logging/LogSource.java
+++ b/src/main/java/org/apache/commons/logging/LogSource.java
@@ -68,6 +68,11 @@ public class LogSource {
     /** Constructor for current log class */
     static protected Constructor logImplctor;
 
+    /**
+     * An empty immutable {@code String} array.
+     */
+    private static final String[] EMPTY_STRING_ARRAY = new String[0];
+
     // ----------------------------------------------------- Class Initializers
 
     static {
@@ -215,6 +220,6 @@ public class LogSource {
      * all logs known to me.
      */
     static public String[] getLogNames() {
-        return (String[]) logs.keySet().toArray(new String[logs.size()]);
+        return (String[]) logs.keySet().toArray(EMPTY_STRING_ARRAY);
     }
 }
diff --git a/src/main/java/org/apache/commons/logging/impl/LogFactoryImpl.java b/src/main/java/org/apache/commons/logging/impl/LogFactoryImpl.java
index deaf8df..d967911 100644
--- a/src/main/java/org/apache/commons/logging/impl/LogFactoryImpl.java
+++ b/src/main/java/org/apache/commons/logging/impl/LogFactoryImpl.java
@@ -77,6 +77,11 @@ public class LogFactoryImpl extends LogFactory {
     private static final String PKG_IMPL="org.apache.commons.logging.impl.";
     private static final int PKG_LEN = PKG_IMPL.length();
 
+    /**
+     * An empty immutable {@code String} array.
+     */
+    private static final String[] EMPTY_STRING_ARRAY = new String[0];
+
     // ----------------------------------------------------------- Constructors
 
     /**
@@ -254,7 +259,7 @@ public class LogFactoryImpl extends LogFactory {
      */
     @Override
     public String[] getAttributeNames() {
-        return (String[]) attributes.keySet().toArray(new String[attributes.size()]);
+        return (String[]) attributes.keySet().toArray(EMPTY_STRING_ARRAY);
     }
 
     /**
@@ -1360,7 +1365,7 @@ public class LogFactoryImpl extends LogFactory {
             }
 
             if (!allowFlawedHierarchy) {
-                final StringBuffer msg = new StringBuffer();
+                final StringBuilder msg = new StringBuilder();
                 msg.append("Terminating logging for this context ");
                 msg.append("due to bad log hierarchy. ");
                 msg.append("You have more than one version of '");
@@ -1373,7 +1378,7 @@ public class LogFactoryImpl extends LogFactory {
             }
 
             if (isDiagnosticsEnabled()) {
-                final StringBuffer msg = new StringBuffer();
+                final StringBuilder msg = new StringBuilder();
                 msg.append("Warning: bad log hierarchy. ");
                 msg.append("You have more than one version of '");
                 msg.append(Log.class.getName());
@@ -1383,7 +1388,7 @@ public class LogFactoryImpl extends LogFactory {
         } else {
             // this is just a bad adapter class
             if (!allowFlawedDiscovery) {
-                final StringBuffer msg = new StringBuffer();
+                final StringBuilder msg = new StringBuilder();
                 msg.append("Terminating logging for this context. ");
                 msg.append("Log class '");
                 msg.append(badClass.getName());
@@ -1396,7 +1401,7 @@ public class LogFactoryImpl extends LogFactory {
             }
 
             if (isDiagnosticsEnabled()) {
-                final StringBuffer msg = new StringBuffer();
+                final StringBuilder msg = new StringBuilder();
                 msg.append("[WARNING] Log class '");
                 msg.append(badClass.getName());
                 msg.append("' does not implement the Log interface.");
diff --git a/src/main/java/org/apache/commons/logging/impl/SimpleLog.java b/src/main/java/org/apache/commons/logging/impl/SimpleLog.java
index 3baf807..ae24c49 100644
--- a/src/main/java/org/apache/commons/logging/impl/SimpleLog.java
+++ b/src/main/java/org/apache/commons/logging/impl/SimpleLog.java
@@ -86,7 +86,7 @@ public class SimpleLog implements Log, Serializable {
     static protected final String DEFAULT_DATE_TIME_FORMAT = "yyyy/MM/dd HH:mm:ss:SSS zzz";
 
     /** Include the instance name in the log message? */
-    static volatile protected boolean showLogName = false;
+    static volatile protected boolean showLogName;
 
     /** Include the short name ( last component ) of the logger in the log
      *  message. Defaults to true - otherwise we'll be lost in a flood of
@@ -95,7 +95,7 @@ public class SimpleLog implements Log, Serializable {
     static volatile protected boolean showShortName = true;
 
     /** Include the current time in the log message */
-    static volatile protected boolean showDateTime = false;
+    static volatile protected boolean showDateTime;
 
     /** The date and time format to use in the log message */
     static volatile protected String dateTimeFormat = DEFAULT_DATE_TIME_FORMAT;
@@ -193,11 +193,11 @@ public class SimpleLog implements Log, Serializable {
     // ------------------------------------------------------------- Attributes
 
     /** The name of this simple log instance */
-    protected volatile String logName = null;
+    protected volatile String logName;
     /** The current log level */
     protected volatile int currentLogLevel;
     /** The short name of this simple log instance */
-    private volatile String shortLogName = null;
+    private volatile String shortLogName;
 
     // ------------------------------------------------------------ Constructor
 
diff --git a/src/main/java/org/apache/commons/logging/impl/WeakHashtable.java b/src/main/java/org/apache/commons/logging/impl/WeakHashtable.java
index 3eea803..9b48bbc 100644
--- a/src/main/java/org/apache/commons/logging/impl/WeakHashtable.java
+++ b/src/main/java/org/apache/commons/logging/impl/WeakHashtable.java
@@ -127,7 +127,7 @@ public final class WeakHashtable extends Hashtable {
     /* ReferenceQueue we check for gc'd keys */
     private final ReferenceQueue queue = new ReferenceQueue();
     /* Counter used to control how often we purge gc'd entries */
-    private int changeCount = 0;
+    private int changeCount;
 
     /**
      * Constructs a WeakHashtable with the Hashtable default
diff --git a/src/test/java/org/apache/commons/logging/PathableClassLoader.java b/src/test/java/org/apache/commons/logging/PathableClassLoader.java
index ee57ca2..4744d9a 100644
--- a/src/test/java/org/apache/commons/logging/PathableClassLoader.java
+++ b/src/test/java/org/apache/commons/logging/PathableClassLoader.java
@@ -395,7 +395,7 @@ public class PathableClassLoader extends URLClassLoader {
     /**
      *
      * Clean implementation of list function of
-     * {@link java.utils.Collection} added in JDK 1.4
+     * {@link java.util.Collection} added in JDK 1.4
      * @param en <code>Enumeration</code>, possibly null
      * @return <code>ArrayList</code> containing the enumerated
      * elements in the enumerated order, not null