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    <p>Do not do that for large files:</p> <pre><code>byte[] bytesToSend = myFile.getBytes(); </code></pre> <p>This is inefficient and you need heap space for storing the whole file data. You're wasting lots of heap space when you first read the file completly and afterwards write it completly.</p> <p>Instead read/write the file data in chunks of specific size from file directly to the response. You can write code on your own or just use a utility class like <code>IOUtils</code> from Apache Commons IO.</p> <p>It is important to not read the whole file first before you write it. Instead do it in smaller chunks. Use streams here and avoid anything that deals with byte[] except for buffering and the small chunks.</p> <p>Edit: Here's some code with Apache IO...</p> <pre><code>public static void main(String[] args) { HttpExchange exchange = ...; OutputStream responseBody = null; try { File file = new File("big-file.txt"); long bytesToSkip = 4711; //detemine how many bytes to skip exchange.sendResponseHeaders(200, file.length() - bytesToSkip); responseBody = exchange.getResponseBody(); skipAndCopy(file, responseBody, bytesToSkip); } catch (IOException e) { // handle it } finally { IOUtils.closeQuietly(responseBody); } } private static void skipAndCopy(File src, @WillNotClose OutputStream dest, long bytesToSkip) throws IOException { InputStream in = null; try { in = FileUtils.openInputStream(src); IOUtils.skip(in, bytesToSkip); IOUtils.copyLarge(in, dest); } finally { IOUtils.closeQuietly(in); } } </code></pre>
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    1. POjava.lang.OutOfMemoryError on HttpServer on download large data
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    1. USFabian Barney
    1. USFabian Barney
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    1. POjava.lang.OutOfMemoryError on HttpServer on download large data
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    1. COThe suggestion regarding the getBytes() doesn't change the exception. i have tried to hold a static reference to byte[] instead of creating it each time. And I still gThe suggestion regarding the getBytes() doesn't change the exception. i have tried to hold a static reference to byte[] instead of creating it each time. And I still get the same exception.et the same exception.
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      1. USSophie
    2. CO@Sophie this guy's explaining it fine, just does not provide implementation details. Tarlog's solution was just wrong, he was reading out the whole file in a different place (the static field).
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    3. CO@Sophie Do not deal with a byte[] holding the whole data. Not at any point in your application. Instead read the file in chunks and write them "on-the-fly" into the response. I recommend to have a look at `IOUtils`.
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      1. USFabian Barney
 

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