Check out example codes for "write file java". It will help you in understanding the concepts better.

Code Example 1

import java.io.FileWriter;   // Import the FileWriter class
import java.io.IOException;  // Import the IOException class to handle errors

public class WriteToFile {
  public static void main(String[] args) {
    try {
      FileWriter myWriter = new FileWriter("filename.txt");
      myWriter.write("Files in Java might be tricky, but it is fun enough!");
      myWriter.close();
      System.out.println("Successfully wrote to the file.");
    } catch (IOException e) {
      System.out.println("An error occurred.");
      e.printStackTrace();
    }
  }
}

Code Example 2

import java.io.File;  // Import the File class
import java.io.IOException;  // Import the IOException class to handle errors

public class CreateFile {
  public static void main(String[] args) {
    try {
      File myObj = new File("filename.txt");
      if (myObj.createNewFile()) {
        System.out.println("File created: " + myObj.getName());
      } else {
        System.out.println("File already exists.");
      }
    } catch (IOException e) {
      System.out.println("An error occurred.");
      e.printStackTrace();
    }
  }
}

Code Example 3

@Test
public void givenUsingJava7_whenWritingToFile_thenCorrect() 
  throws IOException {
    String str = "Hello";
 
    Path path = Paths.get(fileName);
    byte[] strToBytes = str.getBytes();
 
    Files.write(path, strToBytes);
 
    String read = Files.readAllLines(path).get(0);
    assertEquals(str, read);
}

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