I think the deep copy need not involve byte[]. Try the following: public static ByteBuffer clone(ByteBuffer original) { ByteBuffer clone = ByteBuffer.allocate(original.capacity()); original.rewind();//copy from the beginning clone.put(original); original.rewind(); clone.flip(); return clone; }
I suspect that somewhere your application has a reference to the ByteBuffer instance(s) and that is preventing it from being garbage collected. The buffer memory for a direct ByteBuffer is allocated outside of the normal heap (so that the GC doesn’t move it!!). However, the ByteBuffer API provides no method for explicitly disposing of / … Read more
How ByteBuffer works and why Direct (Byte)Buffers are the only truly useful now. first I am a bit surprised it’s not common knowledge but bear it w/ me Direct byte buffers allocate an address outside the java heap. This is utmost importance: all OS (and native C) functions can utilize that address w/o locking the … Read more
Use the FileUtils#readFileToByteArray(File) from Apache Commons IO, and then create the ByteArrayInputStream using the ByteArrayInputStream(byte[]) constructor. public static ByteArrayInputStream retrieveByteArrayInputStream(File file) { return new ByteArrayInputStream(FileUtils.readFileToByteArray(file)); }
After you’ve written to the ByteBuffer, the number of bytes you’ve written can be found with the position() method. If you then flip() the buffer, the number of bytes in the buffer can be found with the limit() or remaining() methods. If you then read some of the buffer, the number of bytes remaining can … Read more
For me the best in this case is Apache commons-io to handle this and similar tasks. The IOUtils type has a static method to read an InputStream and return a byte[]. InputStream is; byte[] bytes = IOUtils.toByteArray(is); Internally this creates a ByteArrayOutputStream and copies the bytes to the output, then calls toByteArray(). UPDATE: as long … Read more
Look at Channels.newChannel(OutputStream). It will give you a channel given an OutputStream. With the WritableByteChannel adapter you can provide the ByteBuffer which will write it to the OutputStream. public void writeBuffer(ByteBuffer buffer, OutputStream stream) { WritableByteChannel channel = Channels.newChannel(stream); channel.write(buffer); } This should do the trick!
After searching for a while and verified through switching the installed JDK between 8 and 11, I have found that there are some changes (new overridden methods) applied to several methods (e.g. flip(), clear() ) in ByteBuffer class. In Java 8, while calling flip() method of ByteBuffer class, since it has no implementation for this … Read more
In order for asynchronous I/O to work, you must have continuous memory. In C you can attempt to re-alloc an array, but in Java you must allocate new memory. You could write to a ByteArrayOutputStream, and then convert it to a ByteBuffer at the time you are ready to send it. The downside is you … Read more
ByteBuffer exposes the bulk get(byte[]) method which transfers bytes from the buffer into the array. You’ll need to instantiate an array of length equal to the number of remaining bytes in the buffer. ByteBuffer buf = … byte[] arr = new byte[buf.remaining()]; buf.get(arr);