Why Arraylist gets cleard after being put to gether in a method?

[Daniel Stallard]

This is where im putting all my methods:

import java.awt.FileDialog;
import java.awt.Frame;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.StringTokenizer;



public class EDMethods{
	
	public static ArrayList<Character> loadData(){
		//Create the ArrayList
		 ArrayList<Character> sentence = new ArrayList<Character>();

			Frame f = new Frame();        
			//decide from where to read the file
			FileDialog foBox = new FileDialog(f,"Select file", FileDialog.LOAD);
			foBox.setVisible(true);
			//get the absolute path to the file
			String foName = foBox.getFile();
			String dirPath = foBox.getDirectory();
		
			// create a file instance for the absolute path
			File inFile = new File(dirPath + foName);
			BufferedReader in=null;
			try
			{
				// create a BufferedReader to use to read in the file
				 in= new BufferedReader(new FileReader(inFile));
				
				// read in the first entire line from the file
				String line = in.readLine();
				StringTokenizer t = new StringTokenizer(line, " ");
				while(t.hasMoreTokens()){
				String ch = t.nextToken().trim();
				Character q = new Character(ch);
				sentence.add(q);
				}//End of while loop
				 line = in.readLine();


					

			}
			// catch any IOException that occurs
			catch (IOException io)
			{
				System.out.println("An IO Exception occurred");
				io.printStackTrace();
			}
			finally
			{
				try
				{
					in.close();
				}
				catch (Exception e){}
			}
			return sentence;
	}
	
	public static void print(ArrayList<Character> sentence)
	{
		System.out.println("The String from the file that was read in");
		for (int i=0;i<sentence.size();i++)
		{
			Character s =  sentence.get(i);				
			System.out.print(s);
		}
		System.out.println("");
	}
	
}

i only have the two in there for now

Here is the menue that i use to call them with:

import java.util.ArrayList;
import java.util.Scanner;






public class EncryptDecrypt {

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		ArrayList<Character> sentence = new ArrayList<Character>();
		int ans=0;
        while (true)
        {
            menu();
            System.out.println("CHOICE:");
            ans = scan.nextInt(); 
            if (ans==1)
            {
            	//Read in a file
            	EDMethods.loadData();
            	
            	
            }
               
            if (ans==2)
            {
            	// Print the file to the console
            	EDMethods.print(sentence);

               
            }
            if (ans==3)
            {
            	// Encrypt the file and write it to the console

            	
            }
            
            if (ans == 4)
            {
            	// Write out the encrypted file to a text file
            	
            }
            
            if (ans == 5)
            {
            	// Clear the data in memory

            }
            
            if (ans==6)
            {
            	//Read in an encrypted file

            }
            if (ans==7)
            {
            	// Decrypt the file

            }
            
            if (ans==8){
            	//Write out the decrypted file
            }
                        
            
            if (ans==9)
            {
            	//End the program
            	System.out.println("See you later!");
            	System.exit(0);
            }
                 
        }
	}

	
	
	public static void menu()
    {
        System.out.println("\n1.  Read in a file ");
        System.out.println("2.  Print the file ");
        System.out.println("3.  Encrypt the file ");
        System.out.println("4.  Write out the encrypted file ");
        System.out.println("5.  Clear the data in memory ");
        System.out.println("6.  Read in the encrypted file ");
        System.out.println("7.  Decrypt the file ");
        System.out.println("8.  Write out the decrypted the file ");
        System.out.println("9.  exit\n"); 
    }
	

}

When i exit the the loadData method and try to print the array list i just made with the data from the txt. file . The array list has nothing in it when i try to print it out. it leave the load data method and clears the array lidt and i also tell it to return the array list.

here is another class i use to keep up with the word i get from the file to put into the array

public class Character extends EncryptDecrypt  {
	private String ch;
	
	public Character(){
	}
	
	public Character (String word){
	this.setCh(ch);
	}

	public String getCh() {
		return ch;
	}

	public void setCh(String ch) {
		this.ch = ch;
	}


}

I just don't understand why the array list goes blank whn it leaves the loadData method.

[Jeanne Boyarsky]

You have two sentence variables in this code.

One is in the loadData() method. It isn't returned so at the end of the message it is eligible for garbage collection.  The main() method has a separate sentence variable that isn't updated.

You can use a return value or a static variable to fix this.

[Daniel Stallard]

the return statement in the load method doesn't work in line 62 of the first chunk of code

[Jeanne Boyarsky]

That's because you don't store the result anywhere. See the difference between these two?

EDMethods.loadData();

sentence = EDMethods.loadData();

The first ignores the result. The second stores it in the sentence variable in the main() method.

[Daniel Stallard]

i actually caught that and fixed it an a few other things.Thanks for pointing it out i had to read your comment a few times for it to click what you was saying now i have a problem with when i try to print to the con sole all it give me is null back an not the strings i put in.

[Daniel Stallard]

okay i do have a question on 34- 40  how would i get it to add the entire line to the array with out splitting it up Ive tried to do away with the tokenizer but i get tons of errors

[Knute Snortum]

The basic loop for reading a file looks like this:

String line = in.readLine();
while (line != null) {
  // do something with line
  line = in.readLine();
}

[Daniel Stallard]

// read in the first entire line from the file
	String line = in.readLine(); // dont understand why this would be in there twice
	StringTokenizer t = new StringTokenizer(line, " ");
	while(line!=null){
		line = in.readLine();if i take this out or leave it it will not add the line to the array	
		sentence.add(line);//it wont let me just add the line to the array ethier wahy i do it 
	}//End of while loop 

[Knute Snortum]

sentence.add(line);

line is a String and sentence is an ArrayList<Character>.  Can you see why you can't add line to sentence?

[Daniel Stallard]

sentence is not the actual array-list? I assume is what you are getting at.

[Knute Snortum]

No, sentence is an ArrayList of Characters, not Strings.