Usage of the [Java] inner class

 PackageTest.file;ImportJava.io.File;ImportJava.io.FilenameFilter;/*** Use of internal classes *@authorFrost.yen * @e-mail [email protected] * @date April 13, 2016*/ Public classTestFile03 { Public Static voidMain (string[] args) {NewTestFile03 (). run (); }    Private voidrun () {File F=NewFile ("E:\\java\\examples\\to learn\\src\\test\\file");        System.out.println (F.exists ());        System.out.println (F.isfile ());        System.out.println (F.isdirectory ()); //string[] Fns = F.list ();//do not filter filesstring[] Fns = F.list (NewJavafilefilter ());//Filter Files         for(String Fn:fns) {System.out.println (FN); } System.out.println ("---------------------------------"); }    /*** Write a class implementation filenamefilter is specifically used to filter the file * (if the class is only accessible inside a class, you can write the class directly inside the class * This class is not accessible externally, this class is called an inner class, the inner class must be static after the Can be declared, so cannot be used in the method of * static) **/    classJavafilefilterImplementsfilenamefilter{@Override Public BooleanAccept (File dir, String name) {//The result of filtering is to display a value that returns True            if(Name.endswith (". Java"))return true; Else return false; }    }}

[Java] inner class usage