No need to allocate empty String arrays over and over.

Author: garydgregory

src/main/java/org/apache/commons/io/FilenameUtils.java

@@ -86,6 +86,8 @@
  */
 public class FilenameUtils {
 
+    private static final String[] EMPTY_STRING_ARRAY = new String[0];
+
     private static final String EMPTY_STRING = "";
 
     private static final int NOT_FOUND = -1;
@@ -1494,7 +1496,7 @@ static String[] splitOnTokens(final String text) {
             list.add(buffer.toString());
         }
 
-        return list.toArray(new String[0]);
+        return list.toArray(EMPTY_STRING_ARRAY);
     }
 
     /**
@@ -1577,7 +1579,7 @@ private static boolean isIPv6Address(final String inet6Address) {
             } else if (inet6Address.startsWith("::") && !octetList.isEmpty()) {
                 octetList.remove(0);
             }
-            octets = octetList.toArray(new String[0]);
+            octets = octetList.toArray(EMPTY_STRING_ARRAY);
         }
         if (octets.length > IPV6_MAX_HEX_GROUPS) {
             return false;

src/main/java/org/apache/commons/io/filefilter/IOFileFilter.java

@@ -29,6 +29,8 @@
  */
 public interface IOFileFilter extends FileFilter, FilenameFilter {
 
+    String[] EMPTY_STRING_ARRAY = new String[0];
+
     /**
      * Checks to see if the File should be accepted by this filter.
      * <p>

src/main/java/org/apache/commons/io/filefilter/NameFileFilter.java

@@ -126,7 +126,7 @@ public NameFileFilter(final List<String> names, final IOCase caseSensitivity) {
         if (names == null) {
             throw new IllegalArgumentException("The list of names must not be null");
         }
-        this.names = names.toArray(new String[0]);
+        this.names = names.toArray(EMPTY_STRING_ARRAY);
         this.caseSensitivity = caseSensitivity == null ? IOCase.SENSITIVE : caseSensitivity;
     }
 

src/main/java/org/apache/commons/io/filefilter/PrefixFileFilter.java

@@ -134,7 +134,7 @@ public PrefixFileFilter(final List<String> prefixes, final IOCase caseSensitivit
         if (prefixes == null) {
             throw new IllegalArgumentException("The list of prefixes must not be null");
         }
-        this.prefixes = prefixes.toArray(new String[0]);
+        this.prefixes = prefixes.toArray(EMPTY_STRING_ARRAY);
         this.caseSensitivity = caseSensitivity == null ? IOCase.SENSITIVE : caseSensitivity;
     }
 

src/main/java/org/apache/commons/io/filefilter/SuffixFileFilter.java

@@ -135,7 +135,7 @@ public SuffixFileFilter(final List<String> suffixes, final IOCase caseSensitivit
         if (suffixes == null) {
             throw new IllegalArgumentException("The list of suffixes must not be null");
         }
-        this.suffixes = suffixes.toArray(new String[0]);
+        this.suffixes = suffixes.toArray(EMPTY_STRING_ARRAY);
         this.caseSensitivity = caseSensitivity == null ? IOCase.SENSITIVE : caseSensitivity;
     }
 

src/main/java/org/apache/commons/io/filefilter/WildcardFileFilter.java

@@ -134,7 +134,7 @@ public WildcardFileFilter(final List<String> wildcards, final IOCase caseSensiti
         if (wildcards == null) {
             throw new IllegalArgumentException("The wildcard list must not be null");
         }
-        this.wildcards = wildcards.toArray(new String[0]);
+        this.wildcards = wildcards.toArray(EMPTY_STRING_ARRAY);
         this.caseSensitivity = caseSensitivity == null ? IOCase.SENSITIVE : caseSensitivity;
     }
 

src/main/java/org/apache/commons/io/filefilter/WildcardFilter.java

@@ -93,7 +93,7 @@ public WildcardFilter(final List<String> wildcards) {
         if (wildcards == null) {
             throw new IllegalArgumentException("The wildcard list must not be null");
         }
-        this.wildcards = wildcards.toArray(new String[0]);
+        this.wildcards = wildcards.toArray(EMPTY_STRING_ARRAY);
     }
 
     //-----------------------------------------------------------------------