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About Ilias Tsagklis

Ilias Tsagklis
Ilias is a software developer turned online entrepreneur. He is co-founder and Executive Editor at Java Code Geeks.

Copy binary file with streams

With this example we are going to demonstrate how to copy a binary file using the FileInputStream and the FileOutputStream. In short, to copy a binary file with streams you should:

  • Create a new FileInputStream, by opening a connection to an actual file, the file named by the path source name in the file system.
  • Create a new FileOutputStream to write to the file with the specified target name.
  • Use read(byte[] b) API method of FileInputStream to read up to b.length bytes of data from this input stream into an array of bytes.
  • Use write(byte[] b, int off, int len) API method of FileOutputStream to write len bytes from the specified byte array starting at offset off to this file output stream.

Let’s take a look at the code snippet that follows:

package com.javacodegeeks.snippets.core;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class CopyBinaryFileWithStreams {
	public static void main(String[] args) {

		String sourceFile = "input.dat";
		String destFile = "output.dat";
		FileInputStream fis = null;
		FileOutputStream fos = null;

		try {
			fis = new FileInputStream(sourceFile);
			fos = new FileOutputStream(destFile);
			byte[] buffer = new byte[1024];
			int noOfBytes = 0;

			System.out.println("Copying file using streams");

			// read bytes from source file and write to destination file
			while ((noOfBytes = fis.read(buffer)) != -1) {
				fos.write(buffer, 0, noOfBytes);
		catch (FileNotFoundException e) {
			System.out.println("File not found" + e);
		catch (IOException ioe) {
			System.out.println("Exception while copying file " + ioe);
		finally {
			// close the streams using close method
			try {
				if (fis != null) {
				if (fos != null) {
			catch (IOException ioe) {
				System.out.println("Error while closing stream: " + ioe);

This was an example of how to copy a binary file with streams in Java.

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