NullPointerException

[oll3i]

nevermind the previous prob i posted

i m getting further and i get a new exception
in readFile method pleae help me with that one
thank u a lot in advance

java.lang.NullP ointerException
at konta_bankowe.I nterfejs.readFi le(Interfejs.ja va)
at konta_bankowe.I nterfejs.wyswie tlHistorieRachu nku(Interfejs.j ava)
at konta_bankowe.I nterfejs.access $0(Interfejs.ja va)
at konta_bankowe.I nterfejs$1.acti onPerformed(Int erfejs.java)
at javax.swing.Abs tractButton.fir eActionPerforme d(Unknown Source)
at javax.swing.Abs tractButton$Han dler.actionPerf ormed(Unknown Source)
at javax.swing.Def aultButtonModel .fireActionPerf ormed(Unknown Source)
at javax.swing.Def aultButtonModel .setPressed(Unk nown Source)
at javax.swing.pla f.basic.BasicBu ttonListener.mo useReleased(Unk nown Source)
at java.awt.Compon ent.processMous eEvent(Unknown Source)
at javax.swing.JCo mponent.process MouseEvent(Unkn own Source)
at java.awt.Compon ent.processEven t(Unknown Source)
at java.awt.Contai ner.processEven t(Unknown Source)
at java.awt.Compon ent.dispatchEve ntImpl(Unknown Source)
at java.awt.Contai ner.dispatchEve ntImpl(Unknown Source)
at java.awt.Compon ent.dispatchEve nt(Unknown Source)
at java.awt.Lightw eightDispatcher .retargetMouseE vent(Unknown Source)
at java.awt.Lightw eightDispatcher .processMouseEv ent(Unknown Source)
at java.awt.Lightw eightDispatcher .dispatchEvent( Unknown Source)
at java.awt.Contai ner.dispatchEve ntImpl(Unknown Source)
at java.awt.Window .dispatchEventI mpl(Unknown Source)
at java.awt.Compon ent.dispatchEve nt(Unknown Source)
at java.awt.EventQ ueue.dispatchEv ent(Unknown Source)
at java.awt.EventD ispatchThread.p umpOneEventForF ilters(Unknown Source)
at java.awt.EventD ispatchThread.p umpEventsForFil ter(Unknown Source)
at java.awt.EventD ispatchThread.p umpEventsForHie rarchy(Unknown Source)
at java.awt.EventD ispatchThread.p umpEvents(Unkno wn Source)
at java.awt.EventD ispatchThread.p umpEvents(Unkno wn Source)
at java.awt.EventD ispatchThread.r un(Unknown Source)




and the code is

package konta_bankowe;



import java.awt.*;
import java.awt.event.*;
import java.beans.*;
import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.text.NumberFormat;

import javax.swing.*;

import static java.awt.Color.*;
import static java.lang.Thread.sleep;
import static java.lang.System.out;

public class Interfejs extends JFrame {

  JTextArea report = new JTextArea(25, 40);
  
  public Interfejs() {
	  setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
	  
	  setTitle("Program kont bankowych(Katarzyna Olbromska).");
      JPanel panel = new JPanel();
      JLabel label = new JLabel("Podaj Number konta :");
      final JTextField numer_konta_field = new JTextField();
      
      numer_konta_field.setColumns(10);
      panel.add(label);
      panel.add(numer_konta_field);
      JButton button = new JButton();
      button.setLabel("Szukaj");
      button.addActionListener( new ActionListener() {
          public void actionPerformed(ActionEvent e) {
  
        		wyswietlHistorieRachunku(numer_konta_field.getText());

        
          }
        });
      panel.add(button);
      getContentPane().add(panel, BorderLayout.SOUTH);
      pack();
      
      
   
    
    report.setBorder(BorderFactory.createTitledBorder("Raport z kont"));
    add(new JScrollPane(report));
    
    JPanel p = new JPanel();

    final JLabel lab = new JLabel("Konta");
    lab.setOpaque(true);
    p.add(lab);
    
    final JButton b1 = new JButton("Złote");
    setColor(YELLOW, b1);
    b1.addActionListener( new ActionListener() {
      public void actionPerformed(ActionEvent e) {
       
      }
    });
    p.add(b1);
        
    final JButton b2 = new JButton("Srebrne");
    Color c1 = new Color(213, 213, 213);
    //g.setColor(c);
    setColor(c1, b2);
    b2.addActionListener( new ActionListener() {
      public void actionPerformed(ActionEvent e) {
       
      }
    });
    p.add(b2);

    final JButton b3 = new JButton("Brązowe");
    Color c2 = new Color(144, 124, 72);
    //g.setColor(c);
    setColor(c2, b3);
    b3.addActionListener( new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        
      }
    });
    p.add(b3);
    
    final JButton b4 = new JButton("Normalne");
    setColor(WHITE, b4);
    b3.addActionListener( new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        
      }
    });
    p.add(b4);
    add(p, "North"); 
    
    pack();
    setVisible(true);
  }
  
  private void setColor(final Color color, final Component ... comps) {
	    
	    for (Component c : comps) c.setBackground(color);
	    
	  }

  private void wyswietlHistorieRachunku(String numer_konta) {
	    report.setText(" "); 
	    //report.append("Numer konta: " +numer_konta +'\n');
	    report.append("Historia Rachunku: " +'\n');
	    readFile(numer_konta);
	  }

	 
	  
private void readFile(String numer_konta){
	
	try{
	    // Open the file that is the first 
	    // command line parameter
	    FileInputStream fstream = new FileInputStream("konta//"+numer_konta+".txt");
	    // Get the object of DataInputStream
	    DataInputStream in = new DataInputStream(fstream);
	    BufferedReader br = new BufferedReader(new InputStreamReader(in));
	    String strLine;
	    String[] historia  = null;
	    
	
	  int n=0;
	  while((strLine = br.readLine()) != null)   {   
	  historia[n]=strLine; 
	  System.out.println("historia[n]="+historia[n]+"strLine="+strLine);
	  n++;
	  }
	  
	  
	  for (String h : historia)
		  report.append(h +'\n');

	
	  
	    in.close();
	  }catch (FileNotFoundException e) {
		    System.err.println("Nie ma takiego konta(File not found!)");
	  }catch (IOException e) {
	          System.err.println(e);
	  }catch (Exception ex)  {
      ex.printStackTrace();  }	
	
	
	
	
}	  
}



package konta_bankowe;


import java.io.*;
import java.util.HashMap;
import java.util.Map;
import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;

public class Konto {
	
	
	/**
	 * @param args
	 */
	protected double sr_dost;
	private String NumerKonta;
	
	 

	        public Konto()
		     { new Interfejs();}
	        
	        public void depozyt( double amount )
			{
				sr_dost += amount;
			}

		        public double wyplata( double amount )
			{
		                // See if amount can be withdrawn
				if (sr_dost >= amount)
				{
					sr_dost -= amount;
		                        return amount;
				}
				else
		                // Withdrawal not allowed
		                        return 0.0;
			}

		        public double get_sr_dost()
			{
		         return sr_dost;
			}     
	        



public static void main(String[] args)throws IOException {
Konto konto = new Konto();

}
}

[sicarie]

Please use code tags ( [ code] and [ /code] without the spaces) - it helps the readability of your posts.

Where is the file you are trying to open? Is it in the same directory, or one below it? It looks like you're using a relative pathname - try using the absolute (which will depend on the machine).

Windows:
C:\\Windows\\....

I'm not sure if that's exactly it, you might have to play around with the slashes - you can use the forward in Windows, but I don't know if you have to backwhack them (adding an extra one so that the compiler reads it as a single slash...) or not.

Linux:
/home/user/docs/yourfile

Once again, you might need to backwhack that...

Try those, see if you are actually pointing to the correct location.

[r035198x]

nevermind the previous prob i posted

i m getting further and i get a new exception
in readFile method pleae help me with that one
thank u a lot in advance

java.lang.NullP ointerException
at konta_bankowe.I nterfejs.readFi le(Interfejs.ja va)
at konta_bankowe.I nterfejs.wyswie tlHistorieRachu nku(Interfejs.j ava)
at konta_bankowe.I nterfejs.access $0(Interfejs.ja va)
at konta_bankowe.I nterfejs$1.acti onPerformed(Int erfejs.java)
at javax.swing.Abs tractButton.fir eActionPerforme d(Unknown Source)
at javax.swing.Abs tractButton$Han dler.actionPerf ormed(Unknown Source)
at javax.swing.Def aultButtonModel .fireActionPerf ormed(Unknown Source)
at javax.swing.Def aultButtonModel .setPressed(Unk nown Source)
at javax.swing.pla f.basic.BasicBu ttonListener.mo useReleased(Unk nown Source)
at java.awt.Compon ent.processMous eEvent(Unknown Source)
at javax.swing.JCo mponent.process MouseEvent(Unkn own Source)
at java.awt.Compon ent.processEven t(Unknown Source)
at java.awt.Contai ner.processEven t(Unknown Source)
at java.awt.Compon ent.dispatchEve ntImpl(Unknown Source)
at java.awt.Contai ner.dispatchEve ntImpl(Unknown Source)
at java.awt.Compon ent.dispatchEve nt(Unknown Source)
at java.awt.Lightw eightDispatcher .retargetMouseE vent(Unknown Source)
at java.awt.Lightw eightDispatcher .processMouseEv ent(Unknown Source)
at java.awt.Lightw eightDispatcher .dispatchEvent( Unknown Source)
at java.awt.Contai ner.dispatchEve ntImpl(Unknown Source)
at java.awt.Window .dispatchEventI mpl(Unknown Source)
at java.awt.Compon ent.dispatchEve nt(Unknown Source)
at java.awt.EventQ ueue.dispatchEv ent(Unknown Source)
at java.awt.EventD ispatchThread.p umpOneEventForF ilters(Unknown Source)
at java.awt.EventD ispatchThread.p umpEventsForFil ter(Unknown Source)
at java.awt.EventD ispatchThread.p umpEventsForHie rarchy(Unknown Source)
at java.awt.EventD ispatchThread.p umpEvents(Unkno wn Source)
at java.awt.EventD ispatchThread.p umpEvents(Unkno wn Source)
at java.awt.EventD ispatchThread.r un(Unknown Source)




and the code is

package konta_bankowe;



import java.awt.*;
import java.awt.event. *;
import java.beans.*;
import java.io.Buffere dReader;
import java.io.DataInp utStream;
import java.io.FileInp utStream;
import java.io.FileNot FoundException;
import java.io.IOExcep tion;
import java.io.InputSt reamReader;
import java.text.Numbe rFormat;

import javax.swing.*;

import static java.awt.Color. *;
import static java.lang.Threa d.sleep;
import static java.lang.Syste m.out;

public class Interfejs extends JFrame {

JTextArea report = new JTextArea(25, 40);

public Interfejs() {
setDefaultClose Operation(JFram e.DISPOSE_ON_CL OSE);

setTitle("Progr am kont bankowych(Katar zyna Olbromska).");
JPanel panel = new JPanel();
JLabel label = new JLabel("Podaj Number konta :");
final JTextField numer_konta_fie ld = new JTextField();

numer_konta_fie ld.setColumns(1 0);
panel.add(label );
panel.add(numer _konta_field);
JButton button = new JButton();
button.setLabel ("Szukaj");
button.addActio nListener( new ActionListener( ) {
public void actionPerformed (ActionEvent e) {

wyswietlHistori eRachunku(numer _konta_field.ge tText());


}
});
panel.add(butto n);
getContentPane( ).add(panel, BorderLayout.SO UTH);
pack();




report.setBorde r(BorderFactory .createTitledBo rder("Raport z kont"));
add(new JScrollPane(rep ort));

JPanel p = new JPanel();

final JLabel lab = new JLabel("Konta") ;
lab.setOpaque(t rue);
p.add(lab);

final JButton b1 = new JButton("Złote" );
setColor(YELLOW , b1);
b1.addActionLis tener( new ActionListener( ) {
public void actionPerformed (ActionEvent e) {

}
});
p.add(b1);

final JButton b2 = new JButton("Srebrn e");
Color c1 = new Color(213, 213, 213);
//g.setColor(c);
setColor(c1, b2);
b2.addActionLis tener( new ActionListener( ) {
public void actionPerformed (ActionEvent e) {

}
});
p.add(b2);

final JButton b3 = new JButton("Brązow e");
Color c2 = new Color(144, 124, 72);
//g.setColor(c);
setColor(c2, b3);
b3.addActionLis tener( new ActionListener( ) {
public void actionPerformed (ActionEvent e) {

}
});
p.add(b3);

final JButton b4 = new JButton("Normal ne");
setColor(WHITE, b4);
b3.addActionLis tener( new ActionListener( ) {
public void actionPerformed (ActionEvent e) {

}
});
p.add(b4);
add(p, "North");

pack();
setVisible(true );
}

private void setColor(final Color color, final Component ... comps) {

for (Component c : comps) c.setBackground (color);

}

private void wyswietlHistori eRachunku(Strin g numer_konta) {
report.setText( " ");
//report.append(" Numer konta: " +numer_konta +'\n');
report.append(" Historia Rachunku: " +'\n');
readFile(numer_ konta);
}



private void readFile(String numer_konta){

try{
// Open the file that is the first
// command line parameter
FileInputStream fstream = new FileInputStream ("konta//"+numer_konta+" .txt");
// Get the object of DataInputStream
DataInputStream in = new DataInputStream (fstream);
BufferedReader br = new BufferedReader( new InputStreamRead er(in));
String strLine;
String[] historia = null;


int n=0;
while((strLine = br.readLine()) != null) {
historia[n]=strLine;
System.out.prin tln("historia[n]="+historia[n]+"strLine="+str Line);
n++;
}


for (String h : historia)
report.append(h +'\n');



in.close();
}catch (FileNotFoundEx ception e) {
System.err.prin tln("Nie ma takiego konta(File not found!)");
}catch (IOException e) {
System.err.prin tln(e);
}catch (Exception ex) {
ex.printStackTr ace(); }




}
}



package konta_bankowe;


import java.io.*;
import java.util.HashM ap;
import java.util.Map;
import java.applet.App let;
import java.awt.*;
import java.awt.event. *;

public class Konto {


/**
* @param args
*/
protected double sr_dost;
private String NumerKonta;



public Konto()
{ new Interfejs();}

public void depozyt( double amount )
{
sr_dost += amount;
}

public double wyplata( double amount )
{
// See if amount can be withdrawn
if (sr_dost >= amount)
{
sr_dost -= amount;
return amount;
}
else
// Withdrawal not allowed
return 0.0;
}

public double get_sr_dost()
{
return sr_dost;
}




public static void main(String[] args)throws IOException {
Konto konto = new Konto();

}
}

1.) Use code tags when posting code.
2.)Do not use DataInputStream for reading a .txt file
Use FileReader fr = new FileReader("fil eName.txt");
BufferedReader br = new BufferedReader( fr);

3.) Here is the reason why you are getting null pointer exception

String[] historia = null;

You initialized this array to null.

int n=0;
while((strLine = br.readLine()) != null) {

There is no problem here ....

...but

historia[n]=strLine;

You try to assign something into an array which you have initialized to null. This will give the NullPointerExce ption.
Either initialize the array first

String[] historia = new String[someInteger];

if you know how many lines there are to read or use an ArrayList to store the lines if you do not know how many lines are going to be read.

[oll3i]

thank you for ur reply
i did what u said me to do and now i'm getting


Exception in thread "AWT-EventQueue-0" java.lang.Error : Unresolved compilation problem:
in cannot be resolved

at konta_bankowe.I nterfejs.readFi le(Interfejs.ja va)
at konta_bankowe.I nterfejs.wyswie tlHistorieRachu nku(Interfejs.j ava)
at konta_bankowe.I nterfejs.access $0(Interfejs.ja va)
at konta_bankowe.I nterfejs$1.acti onPerformed(Int erfejs.java)
at javax.swing.Abs tractButton.fir eActionPerforme d(Unknown Source)
at javax.swing.Abs tractButton$Han dler.actionPerf ormed(Unknown Source)
at javax.swing.Def aultButtonModel .fireActionPerf ormed(Unknown Source)
at javax.swing.Def aultButtonModel .setPressed(Unk nown Source)
at javax.swing.pla f.basic.BasicBu ttonListener.mo useReleased(Unk nown Source)
at java.awt.Compon ent.processMous eEvent(Unknown Source)
at javax.swing.JCo mponent.process MouseEvent(Unkn own Source)
at java.awt.Compon ent.processEven t(Unknown Source)
at java.awt.Contai ner.processEven t(Unknown Source)
at java.awt.Compon ent.dispatchEve ntImpl(Unknown Source)
at java.awt.Contai ner.dispatchEve ntImpl(Unknown Source)
at java.awt.Compon ent.dispatchEve nt(Unknown Source)
at java.awt.Lightw eightDispatcher .retargetMouseE vent(Unknown Source)
at java.awt.Lightw eightDispatcher .processMouseEv ent(Unknown Source)
at java.awt.Lightw eightDispatcher .dispatchEvent( Unknown Source)
at java.awt.Contai ner.dispatchEve ntImpl(Unknown Source)
at java.awt.Window .dispatchEventI mpl(Unknown Source)
at java.awt.Compon ent.dispatchEve nt(Unknown Source)
at java.awt.EventQ ueue.dispatchEv ent(Unknown Source)
at java.awt.EventD ispatchThread.p umpOneEventForF ilters(Unknown Source)
at java.awt.EventD ispatchThread.p umpEventsForFil ter(Unknown Source)
at java.awt.EventD ispatchThread.p umpEventsForHie rarchy(Unknown Source)
at java.awt.EventD ispatchThread.p umpEvents(Unkno wn Source)
at java.awt.EventD ispatchThread.p umpEvents(Unkno wn Source)
at java.awt.EventD ispatchThread.r un(Unknown Source)

[r035198x]

thank you for ur reply
i did what u said me to do and now i'm getting


Exception in thread "AWT-EventQueue-0" java.lang.Error : Unresolved compilation problem:
in cannot be resolved

at konta_bankowe.I nterfejs.readFi le(Interfejs.ja va)
at konta_bankowe.I nterfejs.wyswie tlHistorieRachu nku(Interfejs.j ava)
at konta_bankowe.I nterfejs.access $0(Interfejs.ja va)
at konta_bankowe.I nterfejs$1.acti onPerformed(Int erfejs.java)
at javax.swing.Abs tractButton.fir eActionPerforme d(Unknown Source)
at javax.swing.Abs tractButton$Han dler.actionPerf ormed(Unknown Source)
at javax.swing.Def aultButtonModel .fireActionPerf ormed(Unknown Source)
at javax.swing.Def aultButtonModel .setPressed(Unk nown Source)
at javax.swing.pla f.basic.BasicBu ttonListener.mo useReleased(Unk nown Source)
at java.awt.Compon ent.processMous eEvent(Unknown Source)
at javax.swing.JCo mponent.process MouseEvent(Unkn own Source)
at java.awt.Compon ent.processEven t(Unknown Source)
at java.awt.Contai ner.processEven t(Unknown Source)
at java.awt.Compon ent.dispatchEve ntImpl(Unknown Source)
at java.awt.Contai ner.dispatchEve ntImpl(Unknown Source)
at java.awt.Compon ent.dispatchEve nt(Unknown Source)
at java.awt.Lightw eightDispatcher .retargetMouseE vent(Unknown Source)
at java.awt.Lightw eightDispatcher .processMouseEv ent(Unknown Source)
at java.awt.Lightw eightDispatcher .dispatchEvent( Unknown Source)
at java.awt.Contai ner.dispatchEve ntImpl(Unknown Source)
at java.awt.Window .dispatchEventI mpl(Unknown Source)
at java.awt.Compon ent.dispatchEve nt(Unknown Source)
at java.awt.EventQ ueue.dispatchEv ent(Unknown Source)
at java.awt.EventD ispatchThread.p umpOneEventForF ilters(Unknown Source)
at java.awt.EventD ispatchThread.p umpEventsForFil ter(Unknown Source)
at java.awt.EventD ispatchThread.p umpEventsForHie rarchy(Unknown Source)
at java.awt.EventD ispatchThread.p umpEvents(Unkno wn Source)
at java.awt.EventD ispatchThread.p umpEvents(Unkno wn Source)
at java.awt.EventD ispatchThread.r un(Unknown Source)

Post the code that you have now using code tags.

[oll3i]

i fixed it thank u

[r035198x]

i fixed it thank u

Good for you.

Did you use the FileReader for it then?

[oll3i]

but i get another NullPointerExce ption
in the method below also it doesnt find the rodzaj_konta in string and it goes 2 times through the for loop why

private Map<Integer,Str ing> readFiles(Strin g[] file_names,Stri ng rodzaj_konta) {
Map<Integer,Str ing> map = new HashMap<Integer ,String>();

String wczytane_dane=n ull;
for(int i = 0;i<file_names. length;i++){

boolean jest_rodzaj_kon ta=false;
int j=0;
try{
BufferedReader in = new BufferedReader( new FileReader("kon ta//"+file_name s[i]));

String line = in.readLine();


while (line != null) {
line = in.readLine();
wczytane_dane.c oncat(line);

}


if (wczytane_dane. indexOf(rodzaj_ konta) > 0) {jest_rodzaj_ko nta =true;}

if(jest_rodzaj_ konta){
String numer_konta=nul l;
String[] dane=wczytane_d ane.split(":");
numer_konta=dan e[1];


map.put(j,numer _konta);
j++;
}
in.close();
}catch (FileNotFoundEx ception e) {
System.err.prin tln("File not found!)");
}catch (IOException e) {
System.err.prin tln(e);
}catch (Exception ex) {
ex.printStackTr ace(); }
wczytane_dane=n ull;
}




return map;
}

[oll3i]

it goes through all the files in the directory 2 times

yes i used BufferedReader in = new BufferedReader( new FileReader("kon ta//"+file_name s[i]));

[r035198x]

but i get another NullPointerExce ption
in the method below also it doesnt find the rodzaj_konta in string and it goes 2 times through the for loop why

private Map<Integer,Str ing> readFiles(Strin g[] file_names,Stri ng rodzaj_konta) {
Map<Integer,Str ing> map = new HashMap<Integer ,String>();

String wczytane_dane=n ull;
for(int i = 0;i<file_names. length;i++){

boolean jest_rodzaj_kon ta=false;
int j=0;
try{
BufferedReader in = new BufferedReader( new FileReader("kon ta//"+file_name s[i]));

String line = in.readLine();


while (line != null) {
line = in.readLine();
wczytane_dane.c oncat(line);

}


if (wczytane_dane. indexOf(rodzaj_ konta) > 0) {jest_rodzaj_ko nta =true;}

if(jest_rodzaj_ konta){
String numer_konta=nul l;
String[] dane=wczytane_d ane.split(":");
numer_konta=dan e[1];


map.put(j,numer _konta);
j++;
}
in.close();
}catch (FileNotFoundEx ception e) {
System.err.prin tln("File not found!)");
}catch (IOException e) {
System.err.prin tln(e);
}catch (Exception ex) {
ex.printStackTr ace(); }
wczytane_dane=n ull;
}




return map;
}

There are two possible sources of null pointer this time

String line = in.readLine(); //reads a line
while (line != null) { //tests if it's null that's fine
line = in.readLine(); // reads the next line again! the next line can be null and is null after the last line is read. so
wczytane_dane.c oncat(line); will give a null pointer.

the second source is not definite and may be the arguments you are supplying.
Change the reading to

 String line = in.readLine(); 
	  while (line != null) {
		   wczytane_dane.concat(line);
			line = in.readLine();
	  }

[oll3i]

i moved the line wczytane_dane.c oncat(line);
before
line = in.readLine();

but i still get NullPointerExce ption

[oll3i]

it doesnt even seem to read in the line from file cos i did system.out.prin tln to test it and it displays nothing

here in this while loop

while (line != null) {
wczytane_dane.c oncat(line);
line = in.readLine();
System.out.prin tln("wczytane_d ane"+wczytane_d ane);
}

[oll3i]

i forgot the code tags sorry

[r035198x]

it doesnt even seem to read in the line from file cos i did system.out.prin tln to test it and it displays nothing

here in this while loop

while (line != null) {
wczytane_dane.c oncat(line);
line = in.readLine();
System.out.prin tln("wczytane_d ane"+wczytane_d ane);
}

What is wczytane_dane supposed to be?
Can you post the code for the whole class and a brief explanation of what the code is supposed to do.

[oll3i]

in readFiles i wannna go through the files array passed (this is String[] file_names argument )
then find a word (which is String rodzaj_konta argument)
in a string wczytane_dane(i nto this variable i read in the content of a file line by line cos i wanna look for a word in it)
then i want to return a map if a word searched for is found (that is if rodzaj_konta is found)
rodzaj_konta(it 's in polish but it means account type and it can be "silver" , "brown" "normal" or "golden") so rodzaj_konta variable can have values"silver" , "brown" "normal" or "golden") if rodzaj_konta is found in wczytane_dane then boolean jest_rodzaj_kon ta is to have value true if it is true then i want to add the key and value to map <Intiger,String > key wd be eg 0 and the value wd be the account number got from the file cos i look in wczytane_dane for accout number also

hope u will understand what i wanna do ;]

package konta_bankowe;



import java.awt.*;
import java.awt.event.*;
import java.beans.*;
import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.text.NumberFormat;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import javax.swing.*;

import static java.awt.Color.*;
import static java.lang.Thread.sleep;
import static java.lang.System.out;

public class Interfejs extends JFrame {

  JTextArea report = new JTextArea(25, 40);
  
  public Interfejs() {
	  setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
	  
	  setTitle("Program kont bankowych(Katarzyna Olbromska).");
      JPanel panel = new JPanel();
      JLabel label = new JLabel("Podaj Number konta :");
      final JTextField numer_konta_field = new JTextField();
      
      numer_konta_field.setColumns(10);
      panel.add(label);
      panel.add(numer_konta_field);
      JButton button = new JButton();
      button.setLabel("Szukaj");
      button.addActionListener( new ActionListener() {
          public void actionPerformed(ActionEvent e) {
  
        		wyswietlHistorieRachunku(numer_konta_field.getText());

        
          }
        });
      panel.add(button);
      getContentPane().add(panel, BorderLayout.SOUTH);
      pack();
      
      
   
    
    report.setBorder(BorderFactory.createTitledBorder("Raport z kont"));
    add(new JScrollPane(report));
    
    JPanel p = new JPanel();

    final JLabel lab = new JLabel("Konta");
    lab.setOpaque(true);
    p.add(lab);
    
    final JButton b1 = new JButton("Złote");
    setColor(YELLOW, b1);
    b1.addActionListener( new ActionListener() {
      public void actionPerformed(ActionEvent e) {
    	  wyswietlHistorieRachunkow("zlote");
      }
    });
    p.add(b1);
        
    final JButton b2 = new JButton("Srebrne");
    Color c1 = new Color(213, 213, 213);
    //g.setColor(c);
    setColor(c1, b2);
    b2.addActionListener( new ActionListener() {
      public void actionPerformed(ActionEvent e) {
    	  wyswietlHistorieRachunkow("srebrne");
      }
    });
    p.add(b2);

    final JButton b3 = new JButton("Brązowe");
    Color c2 = new Color(144, 124, 72);
    //g.setColor(c);
    setColor(c2, b3);
    b3.addActionListener( new ActionListener() {
      public void actionPerformed(ActionEvent e) {
    	  wyswietlHistorieRachunkow("brazowe");
      }
    });
    p.add(b3);
    
    final JButton b4 = new JButton("Normalne");
    setColor(WHITE, b4);
    b3.addActionListener( new ActionListener() {
      public void actionPerformed(ActionEvent e) {
    	  wyswietlHistorieRachunkow("normalne");
      }
    });
    p.add(b4);
    add(p, "North"); 
    
    pack();
    setVisible(true);
  }
  
  private void setColor(final Color color, final Component ... comps) {
	    
	    for (Component c : comps) c.setBackground(color);
	    
	  }

  private void wyswietlHistorieRachunku(String numer_konta) {
	    report.setText(" "); 
	    //report.append("Numer konta: " +numer_konta +'\n');
	    report.append("Historia Rachunku: " +'\n');
	    readFile(numer_konta);
	  }

  private void wyswietlHistorieRachunkow(String rodzaj_konta) {
	    report.setText(" "); 
	    //report.append("Numer konta: " +numer_konta +'\n');
	    
	    String[] pliki=listDir("konta");
	    Map<Integer,String> map = new HashMap<Integer,String>();
	    map=readFiles(pliki,rodzaj_konta);
	    System.out.println(map.size());
	    for(int i=0;i<map.size();i++){
	    	System.out.println(map.get(i));
	    wyswietlHistorieRachunku(map.get(i));}
	    
	    
	  }	
  
  
 private String[] listDir(String directory)	{
	  File dir = new File(directory);
	    String[] files = dir.list();
	    if(files == null){
	      System.out.println("Specified directory does not exist or is not a directory.");
	      System.exit(0);
	    }

	 return files;
 }
 
 private Map<Integer,String> readFiles(String[] file_names,String rodzaj_konta)	{
Map<Integer,String> map = new HashMap<Integer,String>();

String wczytane_dane=null;
     for(int i = 0;i<file_names.length;i++){
    	 System.out.println(i+"file_names[i] :"+file_names[i]);
       boolean jest_rodzaj_konta=false; 
       int j=0;
       try{
	    BufferedReader in = new BufferedReader(new FileReader("konta//"+file_names[i]));
	   
	    String line = in.readLine();
	    //System.out.println("line"+line);
	    
	    while (line !=null) {
	    	wczytane_dane.concat(line);
	    	line = in.readLine();
	        System.out.println("wczytane_dane"+wczytane_dane);
	    }
	  
	   // System.out.println("rodzaj_konta"+rodzaj_konta);
	    if (wczytane_dane.indexOf(rodzaj_konta) > 0) {jest_rodzaj_konta =true;}
	    //System.out.println("jest_rodzaj_konta"+jest_rodzaj_konta);
	    if(jest_rodzaj_konta){
	    String numer_konta=null;
	    String[] dane=wczytane_dane.split(":");
	    numer_konta=dane[1];
	    System.out.println("numer_konta(w ifie)"+numer_konta);
	    //report.append(numer_konta +'\n');
	    map.put(j,numer_konta);
        j++;
	    }
	    in.close();
 	  }catch (FileNotFoundException e) {
 		    System.err.println("File not found!)");
 	  }catch (IOException e) {
 	          System.err.println(e);
 	  }catch (Exception ex)  {
       ex.printStackTrace();  }	
 	 wczytane_dane=null;
     }




	 return map;
}
 
 
 
 
private void readFile(String numer_konta){
	
	try{
	    
	    
	    BufferedReader br = new BufferedReader(new FileReader("konta//"+numer_konta+".txt"));
		       
	    
	    
	    
	    String[] historia = new String[6];;
	    String strLine = br.readLine();
	
	  int n=0;
	  while((strLine = br.readLine()) != null)   {   
	  historia[n]=strLine; 
	   n++;
	  }
	  
	  
	  for (String h : historia)
		  report.append(h +'\n');

	
	  
	    br.close();
	  }catch (FileNotFoundException e) {
		    System.err.println("Nie ma takiego konta(File not found!)");
	  }catch (IOException e) {
	          System.err.println(e);
	  }catch (Exception ex)  {
      ex.printStackTrace();  }	
	
	
	
	
}	  
}