The Java Docs for the method
String[] java.io.File.list(FilenameFilter filter)
includes this in the returns description:
The array will be empty if the directory is empty or if no names were accepted by the filter.
How do I do a similar thing and initialize a String array (or any other array for that matter) to have a length 0?
As others have said,
new String[0]
will indeed create an empty array. However, there's one nice thing about arrays - their size can't change, so you can always use the same empty array reference. So in your code, you can use:
private static final String[] EMPTY_ARRAY = new String[0];
and then just return EMPTY_ARRAY each time you need it - there's no need to create a new object each time.
private static final String[] EMPTY_ARRAY = {};
EMPTY_ARRAY[0] - that's trying to access element 0, which doesn't exist...
public static final String[] EMPTY_STRING_ARRAY = new String[0];String[] str = new String[0];?
String[] str = {};
But
return {};
won't work as the type information is missing.
return new String[] { }; and return new String[0]; would both work.Ok I actually found the answer but thought I would 'import' the question into SO anyway
String[] files = new String[0];
or
int[] files = new int[0];
You can use ArrayUtils.EMPTY_STRING_ARRAY from org.apache.commons.lang3
import org.apache.commons.lang3.ArrayUtils;
class Scratch {
public static void main(String[] args) {
String[] strings = ArrayUtils.EMPTY_STRING_ARRAY;
}
}
You can use the following things-
1. String[] str = new String[0];
2. String[] str = ArrayUtils.EMPTY_STRING_ARRAY;
Both are the same.
Make a function which will not return null instead return an empty array you can go through below code to understand.
public static String[] getJavaFileNameList(File inputDir) {
String[] files = inputDir.list(new FilenameFilter() {
@Override
public boolean accept(File current, String name) {
return new File(current, name).isFile() && (name.endsWith("java"));
}
});
return files == null ? new String[0] : files;
}
nullin that special case.