diff --git a/spring-core/src/main/java/org/springframework/core/env/EnumerablePropertySource.java b/spring-core/src/main/java/org/springframework/core/env/EnumerablePropertySource.java
index bcd220e6dd..e63a3c733d 100644
--- a/spring-core/src/main/java/org/springframework/core/env/EnumerablePropertySource.java
+++ b/spring-core/src/main/java/org/springframework/core/env/EnumerablePropertySource.java
@@ -16,10 +16,7 @@
 
 package org.springframework.core.env;
 
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
-
-import org.springframework.util.Assert;
+import org.springframework.util.ObjectUtils;
 
 /**
  * A {@link PropertySource} implementation capable of interrogating its
@@ -41,24 +38,16 @@ import org.springframework.util.Assert;
  * or not.
  *
  * @author Chris Beams
+ * @author Juergen Hoeller
  * @since 3.1
  */
 public abstract class EnumerablePropertySource<T> extends PropertySource<T> {
 
-	protected final Log logger = LogFactory.getLog(getClass());
-
-
 	public EnumerablePropertySource(String name, T source) {
 		super(name, source);
 	}
 
 
-	/**
-	 * Return the names of all properties contained by the
-	 * {@linkplain #getSource() source} object (never {@code null}).
-	 */
-	public abstract String[] getPropertyNames();
-
 	/**
 	 * Return whether this {@code PropertySource} contains a property with the given name.
 	 * <p>This implementation checks for the presence of the given name within the
@@ -67,19 +56,13 @@ public abstract class EnumerablePropertySource<T> extends PropertySource<T> {
 	 */
 	@Override
 	public boolean containsProperty(String name) {
-		Assert.notNull(name, "Property name must not be null");
-		for (String candidate : getPropertyNames()) {
-			if (candidate.equals(name)) {
-				if (logger.isDebugEnabled()) {
-					logger.debug(String.format("PropertySource [%s] contains '%s'", getName(), name));
-				}
-				return true;
-			}
-		}
-		if (logger.isTraceEnabled()) {
-			logger.trace(String.format("PropertySource [%s] does not contain '%s'", getName(), name));
-		}
-		return false;
+		return ObjectUtils.containsElement(getPropertyNames(), name);
 	}
 
+	/**
+	 * Return the names of all properties contained by the
+	 * {@linkplain #getSource() source} object (never {@code null}).
+	 */
+	public abstract String[] getPropertyNames();
+
 }
diff --git a/spring-core/src/main/java/org/springframework/core/env/MapPropertySource.java b/spring-core/src/main/java/org/springframework/core/env/MapPropertySource.java
index 9f9863dc43..0a4a173fa0 100644
--- a/spring-core/src/main/java/org/springframework/core/env/MapPropertySource.java
+++ b/spring-core/src/main/java/org/springframework/core/env/MapPropertySource.java
@@ -18,13 +18,13 @@ package org.springframework.core.env;
 
 import java.util.Map;
 
-import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
 
 /**
  * {@link PropertySource} that reads keys and values from a {@code Map} object.
  *
  * @author Chris Beams
+ * @author Juergen Hoeller
  * @since 3.1
  * @see PropertiesPropertySource
  */
@@ -34,25 +34,20 @@ public class MapPropertySource extends EnumerablePropertySource<Map<String, Obje
 		super(name, source);
 	}
 
+
 	@Override
 	public Object getProperty(String name) {
 		return this.source.get(name);
 	}
 
+	@Override
+	public boolean containsProperty(String name) {
+		return this.source.containsKey(name);
+	}
+
 	@Override
 	public String[] getPropertyNames() {
 		return StringUtils.toStringArray(this.source.keySet());
 	}
 
-	@Override
-	public boolean containsProperty(String name) {
-		Assert.notNull(name, "Property name must not be null");
-		boolean containsProperty = this.source.containsKey(name);
-		if (logger.isDebugEnabled()) {
-			logger.debug(String.format("PropertySource [%s] %s '%s'", getName(),
-					(containsProperty ? "contains" : "does not contain"), name));
-		}
-		return containsProperty;
-	}
-
 }
diff --git a/spring-core/src/main/java/org/springframework/core/env/SystemEnvironmentPropertySource.java b/spring-core/src/main/java/org/springframework/core/env/SystemEnvironmentPropertySource.java
index 3c4d061739..cb4367ebd9 100644
--- a/spring-core/src/main/java/org/springframework/core/env/SystemEnvironmentPropertySource.java
+++ b/spring-core/src/main/java/org/springframework/core/env/SystemEnvironmentPropertySource.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,6 +19,7 @@ package org.springframework.core.env;
 import java.util.Map;
 
 import org.springframework.util.Assert;
+import org.springframework.util.ObjectUtils;
 
 /**
  * Specialization of {@link MapPropertySource} designed for use with
@@ -70,8 +71,9 @@ public class SystemEnvironmentPropertySource extends MapPropertySource {
 		super(name, source);
 	}
 
+
 	/**
-	 * Return true if a property with the given name or any underscore/uppercase variant
+	 * Return {@link true} if a property with the given name or any underscore/uppercase variant
 	 * thereof exists in this property source.
 	 */
 	@Override
@@ -80,13 +82,11 @@ public class SystemEnvironmentPropertySource extends MapPropertySource {
 	}
 
 	/**
-	 * {@inheritDoc}
-	 * <p>This implementation returns {@code true} if a property with the given name or
+	 * This implementation returns {@code true} if a property with the given name or
 	 * any underscore/uppercase variant thereof exists in this property source.
 	 */
 	@Override
 	public Object getProperty(String name) {
-		Assert.notNull(name, "property name must not be null");
 		String actualName = resolvePropertyName(name);
 		if (logger.isDebugEnabled() && !name.equals(actualName)) {
 			logger.debug(String.format("PropertySource [%s] does not contain '%s', but found equivalent '%s'",
@@ -101,23 +101,24 @@ public class SystemEnvironmentPropertySource extends MapPropertySource {
 	 * found or otherwise the original name. Never returns {@code null}.
 	 */
 	private String resolvePropertyName(String name) {
-		if (super.containsProperty(name)) {
+		Assert.notNull(name, "Property name must not be null");
+		if (ObjectUtils.containsElement(getPropertyNames(), name)) {
 			return name;
 		}
 
 		String usName = name.replace('.', '_');
-		if (!name.equals(usName) && super.containsProperty(usName)) {
+		if (!name.equals(usName) && ObjectUtils.containsElement(getPropertyNames(), usName)) {
 			return usName;
 		}
 
 		String ucName = name.toUpperCase();
 		if (!name.equals(ucName)) {
-			if (super.containsProperty(ucName)) {
+			if (ObjectUtils.containsElement(getPropertyNames(), ucName)) {
 				return ucName;
 			}
 			else {
 				String usUcName = ucName.replace('.', '_');
-				if (!ucName.equals(usUcName) && super.containsProperty(usUcName)) {
+				if (!ucName.equals(usUcName) && ObjectUtils.containsElement(getPropertyNames(), usUcName)) {
 					return usUcName;
 				}
 			}
@@ -125,4 +126,5 @@ public class SystemEnvironmentPropertySource extends MapPropertySource {
 
 		return name;
 	}
+
 }