Given two documents input.txt and delete.txt. Our Task is to perform record extraction(Input-Delete) and save the yield in document say output.txt.

Naive Algorithm :

1. Create PrintWriter object for output.txt
2. Open BufferedReader for input.txt
3. Run a loop for each line of input.txt
   3.1 flag = false
   3.2 Open BufferedReader for delete.txt
   3.3 Run a loop for each line of delete.txt
      ->  If  line of delete.txt is equal to current line of input.txt 
            -> flag = true
            -> break loop

4. Check flag, if false
     -> write current line of input.txt to output.txt
5. Flush PrintWriter stream and close resources.

To effectively run the underneath program input.txt and delete.txt must ways out in same envelope OR give full way to them.

// Java program to perform file
// operation output = input-delete

import java.io.*;

public class FileOperation
{
	public static void main(String[] args) throws IOException
	{
		// PrintWriter object for output.txt
		PrintWriter pw = new PrintWriter("output.txt");
		
		// BufferedReader object for input.txt
		BufferedReader br1 = new BufferedReader(new FileReader("input.txt"));
		
		String line1 = br1.readLine();
		
		// loop for each line of input.txt
		while(line1 != null)
		{
			boolean flag = false;
			
			// BufferedReader object for delete.txt
			BufferedReader br2 = new BufferedReader(new FileReader("delete.txt"));
			
			String line2 = br2.readLine();
			
			// loop for each line of delete.txt
			while(line2 != null)
			{
				if(line1.equals(line2))
				{
					flag = true;
					break;
				}
				
				line2 = br2.readLine();
			}
			
			// if flag = false
			// write line of input.txt to output.txt
			if(!flag)
				pw.println(line1);
			
			line1 = br1.readLine();
			
		}
		
		pw.flush();
		
		// closing resources
		br1.close();
		pw.close();
		
		System.out.println("File operation performed successfully");
	}
}

Output:

File operation performed successfully

Note : On the off chance that output.txt exist in cwd (current working catalog) it will be overwritten by above program in any case new document will be made.

A superior arrangement is to utilize HashSet to store each line of delete.txt and afterward while circling through lines of input.txt ,check on the off chance that it is in hashset. If not present, compose that line into output.txt.

To effectively run the underneath program input.txt and delete.txt must ways out in same organizer OR give full way to them.

// Efficient Java program to perform file
// operation output = input-delete

import java.io.*;
import java.util.HashSet;

public class FileOperation
{
	public static void main(String[] args) throws IOException
	{
		// PrintWriter object for output.txt
		PrintWriter pw = new PrintWriter("output.txt");
		
		// BufferedReader object for delete.txt
		BufferedReader br2 = new BufferedReader(new FileReader("delete.txt"));
		
		String line2 = br2.readLine();
		
		// hashset for storing lines of delete.txt
		HashSet hs = new HashSet();
		
		// loop for each line of delete.txt
		while(line2 != null)
		{
			hs.add(line2);
			line2 = br2.readLine();
		}
					
		// BufferedReader object for input.txt
		BufferedReader br1 = new BufferedReader(new FileReader("input.txt"));
		
		String line1 = br1.readLine();
		
		// loop for each line of input.txt
		while(line1 != null)
		{
			// if line is not present in delete.txt
			// write it to output.txt
			if(!hs.contains(line1))
				pw.println(line1);
			
			line1 = br1.readLine();
		}
		
		pw.flush();
		
		// closing resources
		br1.close();
		br2.close();
		pw.close();
		
		System.out.println("File operation performed successfully");
	}
}

Output:

File operation performed successfully

Note : If output.txt exist in cwd(current working directory) then it will be overwritten by above program otherwise new file will be created.