Write byte array to file with FileOutputStream

With this example we are going to demonstrate how to write a byte array to a file using a FileOutputStream. The FileOutputStream is an output stream for writing data to a File or to a FileDescriptor. In short, to write a byte array to a file using a FileOutputStream you should:

  • Create a new File instance by converting the given pathname string into an abstract pathname.
  • Create a new FileOutputStream to write to the file represented by the specified File object.
  • Write bytes from a specified byte array to this file output stream, using write(byte[] b) API method.
  • Don’t forget to close the stream, using its close() API method.

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

package com.javacodegeeks.snippets.core;


public class WriteByteArrayToFileWithileOutputStream {
	public static void main(String[] args) {
		String s = "Java Code Geeks - Java Examples";
		File file = new File("outputfile.txt");
		FileOutputStream fos = null;

		try {
			fos = new FileOutputStream(file);
			// Writes bytes from the specified byte array to this file output stream 

		catch (FileNotFoundException e) {
			System.out.println("File not found" + e);
		catch (IOException ioe) {
			System.out.println("Exception while writing file " + ioe);
		finally {
			// close the streams using close method
			try {
				if (fos != null) {
			catch (IOException ioe) {
				System.out.println("Error while closing stream: " + ioe);



This was an example of how to write a byte array to a file using a FileOutputStream in Java.

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Byron Kiourtzoglou

Byron is a master software engineer working in the IT and Telecom domains. He is an applications developer in a wide variety of applications/services. He is currently acting as the team leader and technical architect for a proprietary service creation and integration platform for both the IT and Telecom industries in addition to a in-house big data real-time analytics solution. He is always fascinated by SOA, middleware services and mobile development. Byron is co-founder and Executive Editor at Java Code Geeks.
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