java - Do you think I'm abusing of statics? -

i'm new in java programming , think have clear objects , how work them.

however, i'm writing program have noticed have used lot 'static' keyword methods, , i'm doubting if because neccesary , logical or if because have not internalized in mind oo concepts.

to more specific, program should read txt file , put each line in arraylist, code:

public class filebody {      private static final string separator = ";";     private static string headerfield1 = "regex";     private static string headerfield2 = "origin";     private static string headerfield3 = "destination";     private static final string header = headerfield1 + separator + headerfield2             + separator + headerfield3 + separator;      // getters & setters      public static string getheader() {         return header;     }      public static string getheaderfield1() {         return headerfield1;     }      public static void setheaderfield1(string headerfield1) {         filebody.headerfield1 = headerfield1;     }      public static string getheaderfield2() {         return headerfield2;     }      public static void setheaderfield2(string headerfield2) {         filebody.headerfield2 = headerfield2;     }      public static string getheaderfield3() {         return headerfield3;     }      public static void setheaderfield3(string headerfield3) {         filebody.headerfield3 = headerfield3;     }      // end getters & setters      public static file createfileifnotexists(string path) throws ioexception {         file file = new file(path);         if (file.createnewfile());         return file;     }      public static file getfile(string path) throws ioexception {         file file = createfileifnotexists(path);         return file;     }      public static boolean isempty(file file) throws exception {         filereader filereader = new filereader(file);         if (filereader.read() != -1) {             filereader.close();             return false;         } else {             filereader.close();             return true;         }     }      public static void writeheadertoemptyfile(file file) throws exception {         if (isempty(file)) {             bufferedwriter bufferedwriter = new bufferedwriter(                     new filewriter(file, false));             bufferedwriter.write(header);             bufferedwriter.close();         } else {             return;         }     }      public static arraylist<string> getlines(file file) throws exception {         arraylist<string> lines = new arraylist<>();         bufferedreader bufferedreader = new bufferedreader(new filereader(file));         while (bufferedreader.ready()) {             lines.add(bufferedreader.readline());         }         bufferedreader.close();         return lines;     }  } 

do think have done better objects? if answer yes, give me guidelines that?

thank help.

having mutable static fields should avoided where-ever possible. in particular, have won't work because initalised once.

// run once if these fields changed. private static final string header = headerfield1 + separator + headerfield2         + separator + headerfield3 + separator; 

most want is

public static string getheader() {     return headerfield1 + separator + headerfield2         + separator + headerfield3 + separator; } 

the field should static separator constant. try make other fields non-static fields (and getter/setters)

you have utility/helper methods @ end of class. put these in class don't appear related. i.e. have clear utility class these methods instead. e.g.

class filebody {     public void writeheadertoemptyfile(file file) throws ioexception {         if (!fileutils.isempty(file)) return         try (writer w = new filewriter(file)) {             w.write(getheader());         }     } }  class enum fileutils {     /* no instances */ ;      // todo replace callers new file(x);     public static file getfile(string filename) {           return new file(filename);     }      public static boolean isempty(file file) {         return file.length() > 0;     }      public static list<string> getlines(file file) throws exception {         return files.readalllines(paths.get(file.getabsolutepath()));     } }