DECLARE
  l_exists     boolean;
  l_size       integer;
  l_block_size integer;
BEGIN
  utl_file.fgetattr( 'EXPBKUP', 
                     'import.log', 
                     l_exists, 
                     l_size, 
                     l_block_size );
   if( l_exists )
   then
     dbms_output.put_line( 'The file exists and has a size of ' || l_size );
   else
     dbms_output.put_line( 'The file does not exist or is not visible to Oracle' );
   end if;
END;

The file exists and has a size of 598

CREATE or REPLACE AND COMPILE JAVA SOURCE NAMED "GetFile" AS
 
import java.lang.*;
import java.util.*;
import java.io.*;
import java.sql.Timestamp;
 
public class GetFile {
  private static int KO = 0; 
  private static int OK = 1;

  public static int exists (String p_file) {
    File l_file = new File (p_file);
    if (l_file.exists()) return OK; else return KO;
  }

  public static String name (String p_file) {
    File l_file = new File (p_file);
    return l_file.getName();
  }

  public static String path (String p_file) {
    File l_file = new File (p_file);
    return l_file.getParent();
  }

  public static String absolutePath (String p_file) {
    File l_file = new File (p_file);
    String res = l_file.getAbsolutePath();
    res = res.substring(0,res.length()-l_file.getName().length()-1);
    return res;
  }

  public static int isFile (String p_file) {
    File l_file = new File (p_file);
    if (l_file.isFile()) return OK; else return KO;
  }

  public static int isDirectory (String p_file) {
    File l_file = new File (p_file);
    if (l_file.isDirectory()) return OK; else return KO;
  }

  public static int isHidden (String p_file) {
    File l_file = new File (p_file);
    if (l_file.isHidden()) return OK; else return KO;
  }

  public static int canRead (String p_file) {
    File l_file = new File (p_file);
    if (l_file.canRead()) return OK; else return KO;
  }

  public static int canWrite (String p_file) {
    File l_file = new File (p_file);
    if (l_file.canWrite()) return OK; else return KO;
  }

  public static Timestamp lastModified (String p_file) {
    File l_file = new File (p_file);
    return new Timestamp(l_file.lastModified());
  }

  public static long length (String p_file) {
    File l_file = new File (p_file);
    return l_file.length();
  }
  
}
/
SHOW ERRORS
 
CREATE OR REPLACE PACKAGE get_file AS

  FUNCTION exists (p_file IN VARCHAR2) RETURN NUMBER
  AS LANGUAGE JAVA 
  NAME 'GetFile.exists (java.lang.String) return java.lang.int';

  FUNCTION name (p_file IN VARCHAR2) RETURN VARCHAR2
  AS LANGUAGE JAVA 
  NAME 'GetFile.name (java.lang.String) return java.lang.String';

  FUNCTION path (p_file IN VARCHAR2) RETURN VARCHAR2
  AS LANGUAGE JAVA 
  NAME 'GetFile.path (java.lang.String) return java.lang.String';

  FUNCTION absolute_path (p_file IN VARCHAR2) RETURN VARCHAR2
  AS LANGUAGE JAVA 
  NAME 'GetFile.absolutePath (java.lang.String) return java.lang.String';

  FUNCTION is_file (p_file IN VARCHAR2) RETURN NUMBER
  AS LANGUAGE JAVA 
  NAME 'GetFile.isFile (java.lang.String) return java.lang.int';

  FUNCTION is_directory (p_file IN VARCHAR2) RETURN NUMBER
  AS LANGUAGE JAVA 
  NAME 'GetFile.isDirectory (java.lang.String) return java.lang.int';

  FUNCTION is_hidden (p_file IN VARCHAR2) RETURN NUMBER
  AS LANGUAGE JAVA 
  NAME 'GetFile.isHidden (java.lang.String) return java.lang.int';

  FUNCTION can_read (p_file IN VARCHAR2) RETURN NUMBER
  AS LANGUAGE JAVA 
  NAME 'GetFile.canRead (java.lang.String) return java.lang.int';

  FUNCTION can_write (p_file IN VARCHAR2) RETURN NUMBER
  AS LANGUAGE JAVA 
  NAME 'GetFile.canWrite (java.lang.String) return java.lang.int';

  FUNCTION last_modified (p_file IN VARCHAR2) RETURN DATE
  AS LANGUAGE JAVA 
  NAME 'GetFile.lastModified (java.lang.String) return java.sql.Timestamp';

  FUNCTION length (p_file IN VARCHAR2) RETURN NUMBER
  AS LANGUAGE JAVA 
  NAME 'GetFile.length (java.lang.String) return java.lang.long';

END;
/
SHOW ERRORS

TEST> DECLARE
  2    l_file VARCHAR2(50);
  3  BEGIN
  4    l_file := '.\NETWORK\ADMIN\tnsnames.ora';
  5    dbms_output.put_line(rpad(' ',20)||' '||l_file);
  6    dbms_output.put_line(rpad(' ',20)||' '||rpad('-',length(l_file),'-'));
  7    dbms_output.new_line;
  8    dbms_output.put_line(rpad('Exists?',20,'.')||' '||get_file.exists(l_file));
  9    dbms_output.put_line(rpad('Name',20,'.')||' '||get_file.name(l_file));
 10    dbms_output.put_line(rpad('Path',20,'.')||' '||get_file.path(l_file));
 11    dbms_output.put_line(rpad('Absolute path',20,'.')||' '||get_file.absolute_path(l_file));
 12    dbms_output.put_line(rpad('Is file?',20,'.')||' '||get_file.is_file(l_file));
 13    dbms_output.put_line(rpad('Is directory?',20,'.')||' '||get_file.is_directory(l_file));
 14    dbms_output.put_line(rpad('Is hidden?',20,'.')||' '||get_file.is_hidden(l_file));
 15    dbms_output.put_line(rpad('Can read?',20,'.')||' '||get_file.can_read(l_file));
 16    dbms_output.put_line(rpad('Can write?',20,'.')||' '||get_file.can_write(l_file));
 17    dbms_output.put_line(rpad('Exists',20,'.')||' '||get_file.exists(l_file));
 18    dbms_output.put_line(rpad('Last modified',20,'.')||' '||
 19                         TO_CHAR(get_file.last_modified(l_file),'DD/MM/YYYY HH24:MI:SS'));
 20    dbms_output.put_line(rpad('Length',20,'.')||' '||get_file.length(l_file));
 21  END;
 22  /
                     .\NETWORK\ADMIN\tnsnames.ora
                     ----------------------------

Exists?............. 1
Name................ tnsnames.ora
Path................ .\NETWORK\ADMIN
Absolute path....... E:\ORACLE\ORA11204\.\NETWORK\ADMIN
Is file?............ 1
Is directory?....... 0
Is hidden?.......... 0
Can read?........... 1
Can write?.......... 1
Exists.............. 1
Last modified....... 15/01/2018 11:35:34
Length.............. 4540

PL/SQL procedure successfully completed.

GRANT JAVAUSERPRIV TO <user>;
BEGIN
  DBMS_JAVA.grant_permission('<user>', 'java.io.FilePermission', '<<ALL FILES>>', 'read');
  DBMS_JAVA.grant_permission('<user>', 'SYS:java.lang.RuntimePermission', 'readFileDescriptor', '');
END;
/