Performance Enhancement: Call toArray with Zero Array Size (closes #65)

toArray should, at least since Java 7, be used with new T[0] instead of size, since it is "faster, safer, and contractually cleaner" (https://shipilev.net/blog/2016/arrays-wisdom-ancients/#_conclusion)

Author: DaGeRe

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

@@ -1494,7 +1494,7 @@ static String[] splitOnTokens(final String text) {
             list.add(buffer.toString());
         }
 
-        return list.toArray( new String[ list.size() ] );
+        return list.toArray( new String[ 0 ] );
     }
 
     /**
@@ -1577,7 +1577,7 @@ private static boolean isIPv6Address(final String inet6Address) {
             } else if (inet6Address.startsWith("::") && !octetList.isEmpty()) {
                 octetList.remove(0);
             }
-            octets = octetList.toArray(new String[octetList.size()]);
+            octets = octetList.toArray(new String[0]);
         }
         if (octets.length > IPV6_MAX_HEX_GROUPS) {
             return false;

src/main/java/org/apache/commons/io/comparator/CompositeFileComparator.java

@@ -76,7 +76,7 @@ public CompositeFileComparator(final Iterable<Comparator<File>> delegates) {
             for (final Comparator<File> comparator : delegates) {
                 list.add(comparator);
             }
-            this.delegates = (Comparator<File>[]) list.toArray(new Comparator<?>[list.size()]); //2
+            this.delegates = (Comparator<File>[]) list.toArray(new Comparator<?>[0]); //2
         }
     }
 

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

@@ -89,7 +89,7 @@ public static File[] filter(final IOFileFilter filter, final File... files) {
                 acceptedFiles.add(file);
             }
         }
-        return acceptedFiles.toArray(new File[acceptedFiles.size()]);
+        return acceptedFiles.toArray(new File[0]);
     }
 
     /**
@@ -120,7 +120,7 @@ public static File[] filter(final IOFileFilter filter, final File... files) {
      */
     public static File[] filter(final IOFileFilter filter, final Iterable<File> files) {
         final List<File> acceptedFiles = filterList(filter, files);
-        return acceptedFiles.toArray(new File[acceptedFiles.size()]);
+        return acceptedFiles.toArray(new File[0]);
     }
 
     /**

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[names.size()]);
+        this.names = names.toArray(new String[0]);
         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[prefixes.size()]);
+        this.prefixes = prefixes.toArray(new String[0]);
         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[suffixes.size()]);
+        this.suffixes = suffixes.toArray(new String[0]);
         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[wildcards.size()]);
+        this.wildcards = wildcards.toArray(new String[0]);
         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[wildcards.size()]);
+        this.wildcards = wildcards.toArray(new String[0]);
     }
 
     //-----------------------------------------------------------------------