Java: Append text to an existing file

Last update on April 28 2025 07:37:12 (UTC/GMT +8 hours)

Write a Java program to write and read a plain text file.

Sample Solution:

Java Code:

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.FileInputStream;
import java.io.FileReader;
import java.io.FileWriter;
 
public class Exercise16 {
     public static void main(String a[]){
        StringBuilder sb = new StringBuilder();
        String strLine = "";
        try
          {
             String filename= "/home/students/myfile.txt";
             FileWriter fw = new FileWriter(filename,true); 
             //appends the string to the file
             fw.write("Java Exercises\n");
             fw.close();
             BufferedReader br = new BufferedReader(new FileReader("/home/students/myfile.txt"));
             //read the file content
             while (strLine != null)
             {
                sb.append(strLine);
                sb.append(System.lineSeparator());
                strLine = br.readLine();
                System.out.println(strLine);
            }
             br.close();
           }
           catch(IOException ioe)
           {
            System.err.println("IOException: " + ioe.getMessage());
           }
        }
  }

Sample Output:

Python Exercises                                                                                              
Java Exercises                                                                                                
null

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Java program to append a new line of text to an existing file using FileWriter in append mode.
• Write a Java program to add text to the end of a file without overwriting its current content.
• Write a Java program to append user-provided text to a file and then display the updated file content.
• Write a Java program to repeatedly append lines to a file and then count the total number of lines present.

Java Code Editor:

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