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File Copy Using Java NIO

I wanted to post this small piece of code for those who are looking for it. Copying file contents using Streams is old way of doing, Java New IO is the way to go; using Java NIO is better in terms of performance.
Following is the code to do file copy using Java NIO.

public static void copyFile(File src, File dest) throws IOException {
    if (!src.exists()) {
        // either return quietly OR throw an exception
    if (!dest.exists()) {

    FileChannel source = new FileInputStream(src).getChannel();
    try {
        FileChannel destination = new FileOutputStream(dest).getChannel();
        try {
            source.transferTo(0, source.size(), destination);
            // destination.transferFrom(source, 0, source.size());
        } finally {
            if (destination != null) {
    } finally {
        if (source != null) {

By using NIO classes, we don’t need to create those byte buffers, loop through and copy in chunks, etc. NIO code is clean and simple, below line of code is the one responsible for copying file content.

source.transferTo(0, source.size(), destination); 

Quite simple isn’t it. It gets even simpler in Java7, all we need is one line of code as given below

Files.copy(src, dest);

// OR

Files.copy(src, dest, StandardCopyOption.REPLACE_EXISTING);

In the above line of code ‘src’ and ‘dest’ are not instances of class, but they are of type "java.nio.file.Path". You can get Path object instance either by calling "toPath()" method on "java.iolFile" class object, OR creating one by calling the "getPath()" method on "java.nio.file.FileSystem" object.

FileSystems.getDefault().getPath("logs", "access.log");

The above line of code will give you an instance of ‘java.nio.file.Path’, which points to a file ‘access.log’ available in ‘logs’ directory, path is relative to current directory ["./logs/access.log"]. You can find more information @


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About Rakesh.A

As the URL and other parts of this blog says, I am Rakesh.A, a techie form Hyderabad, India. I am working for coMakeIT, Hyderabad as a Sr. Software Engineer, that's about me in short.
How I ended up in this profession? - Well when I was doing my schooling I never thought I'll be into this profession, infact I wasn't that interested in Information Technology/Software Development, so never concentrated on it even after my parents stressed to get into it. After couple of years, I saw myself doing the same. And now I can't even think of myself being in a different profession. Anything I can do with whole heart, that's only PROGRAMMING/DEVELOPMENT.
As every student who got into this profession, I felt my FIRST LOVE with 'C language', and I love coding in C. Then I started learning Object Oriented Programming and got attracted to 'C++ language', but it was 'JAVA' in which I saw my soul mate. That's it I got married to it and settled. I've…