I guess this is better?

src/checkstyle/com/puppycrawl/tools/checkstyle/DefaultContext.java

@@ -19,9 +19,10 @@
 package com.puppycrawl.tools.checkstyle;
 
 import com.puppycrawl.tools.checkstyle.api.Context;
+import java.util.Collection;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
-import java.util.Set;
 
 /**
  * A default implementation of the Context interface.
@@ -39,10 +40,9 @@ public final class DefaultContext implements Context
     }
 
     /** {@inheritDoc} */
-    public String[] getAttributeNames()
+    public Collection<String> getAttributeNames()
     {
-        final Set<String> keySet = mEntries.keySet();
-        return keySet.toArray(new String[keySet.size()]);
+        return Collections.unmodifiableCollection(mEntries.keySet());
     }
 
     /**

src/checkstyle/com/puppycrawl/tools/checkstyle/api/AutomaticBean.java

@@ -21,6 +21,7 @@ package com.puppycrawl.tools.checkstyle.api;
 import java.beans.PropertyDescriptor;
 import java.lang.reflect.InvocationTargetException;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
 import java.util.StringTokenizer;
 import org.apache.commons.beanutils.BeanUtilsBean;
@@ -219,7 +220,7 @@ public class AutomaticBean
         final BeanUtilsBean beanUtils = createBeanUtilsBean();
 
         // TODO: debug log messages
-        final String[] attributes = aContext.getAttributeNames();
+        final Collection<String> attributes = aContext.getAttributeNames();
 
         for (final String key : attributes) {
             final Object value = aContext.get(key);

src/checkstyle/com/puppycrawl/tools/checkstyle/api/Context.java

@@ -18,6 +18,8 @@
 ////////////////////////////////////////////////////////////////////////////////
 package com.puppycrawl.tools.checkstyle.api;
 
+import java.util.Collection;
+
 /**
  * A context to be used in subcomponents. The general idea of
  * Context/Contextualizable was taken from <a target="_top"
@@ -38,5 +40,5 @@ public interface Context
      * Returns the names of all atttributes of this context.
      * @return the names of all atttributes of this context.
      */
-    String[] getAttributeNames();
+    Collection<String> getAttributeNames();
 }