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copied!<blockquote> <p>I have to use Random Access Files because I need to write to different positions in file.</p> </blockquote> <p>No, you don't. You can reposition a <code>FileOutputStream</code> or <code>FileInputStream</code> via its channel.</p> <p>That would significantly simplify your writing code as well: you wouldn't need to use the buffer or channel, and depending on your needs you could omit the <code>ByteArrayOutputStream</code> as well. However, as you note in a comment, you won't know the size of the object in advance, and the <code>ByteArrayOutputStream</code> is a useful way to verify that you don't overrun your allotted space.</p> <pre><code>Object obj = // something FileOutputStream fos = // an initialized stream ByteArrayOutputStream bos = new ByteArrayOutputStream(); ObjectOutputStream oos = new ObjectOutputStream(bos); oos.writeObject(obj); oos.flush(); if (bos.size() > MAX_ALLOWED_SIZE) throw // or log, or whatever you want to do else { fos.getChannel().position(writeLocation); bos.writeTo(fos); } </code></pre> <p>To read the objects, do the following:</p> <pre><code>FileInputStream fis = // an initialized stream fis.getChannel().position(offsetOfSerializedObject); ObjectInputStream iis = new ObjectInputStream(new BufferedInputStream(fis)); Object obj = iis.readObject(); </code></pre> <p>One comment here: I wrapped the <code>FileInputStream</code> in a <code>BufferedInputStream</code>. In this specific case, where the file stream is repositioned before each use, that can provide a performance benefit. Be aware, however, that the buffered stream can read more bytes than are needed, and there are some situations using construct-as-needed object streams where it would be a really bad idea.</p>

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