Read all the files in a folder

public void listarFicherosPorCarpeta(final File carpeta) {
    for (final File ficheroEntrada : carpeta.listFiles()) {
        if (ficheroEntrada.isDirectory()) {
            listarFicherosPorCarpeta(ficheroEntrada);
        } else {
            System.out.println(ficheroEntrada.getName());
        }
    }
}

final File carpeta = new File("/home/usuario/Escritorio");
listarFicherosPorCarpeta(carpeta );

With Java 8 it would work like this:

Files.walk(Paths.get("/home/usuario/Escritorio")).forEach(ruta-> {
    if (Files.isRegularFile(ruta)) {
        System.out.println(ruta);
    }
});

Translated and adapted from SO Eng .

import java.io.File;
import java.util.ArrayList;
import java.util.List;

class Test {

        public static void main( String[] args ) {

            String path = "d://rererer/";


            String[] files = getFiles( path );

            if ( files != null ) {

                int size = files.length;

                for ( int i = 0; i < size; i ++ ) {

                    System.out.println( files[ i ] );
                }
            }
        }


        public static String[] getFiles( String dir_path ) {

            String[] arr_res = null;

            File f = new File( dir_path );

            if ( f.isDirectory( )) {

                List<String> res   = new ArrayList<>();
                File[] arr_content = f.listFiles();

                int size = arr_content.length;

                for ( int i = 0; i < size; i ++ ) {

                    if ( arr_content[ i ].isFile( ))
                    res.add( arr_content[ i ].toString( ));
                }


                arr_res = res.toArray( new String[ 0 ] );

            } else
                System.err.println( "¡ Path NO válido !" );


            return arr_res;
        }

} //class

For the example, just change the value of path in main () to list the files in the directory you want.