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Java I/O Q&A
2.batch File
3.binary File
4.class file
5.CSV file
10.Excel File
11.File Attribute
14.Media File
17.PDF file
20.text file
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Java I/O Q&A » API » ByteBuffer 

1. Java bytebuffer to C

From a C program on Windows we need to read and write like a Java bytebuffer which stores binary in BIG_ENDIAN The algorithm is described at : Need to read and ...

2. How to initialize a ByteBuffer if you don't know how many bytes to allocate beforehand?

Is this:

ByteBuffer buf = ByteBuffer.allocate(1000);
...the only way to initialize a ByteBuffer? What if I have no idea how many bytes I need to allocate..? Edit: More details: I'm converting one image file format to ...

3. Java - ByteBuffer.remaining() problems

Summary: I have a ByteBuffer in which I am pumping some data. After that, I want to send this data over a Socket. So, I wrote code like this:


4. JNA ByteBuffer statvfs

I am trying to get the free space on the / folder using statvfs call from java, I have check the size of statvfs struct from c it shows 44 bytes, I ...

5. Growing ByteBuffer

Has anyone has ever seen an implementation of java.nio.ByteBuffer that will grow dynamically if a putX() call overruns the capacity? The reason I want to do it this way is twofold: 1) I ...

6. ByteBuffer, what is a clean way to detect if it needs to be flipped

Is there a clean sure fire way to detect if a ByteBuffer needs flipping? I have a ByteBuffer that is used for packing and unpacking a data stucture and also for ...

7. ByteBuffer recycling class

I'm wonder how I'd code up a ByteBuffer recycling class that can get me a ByteBuffer which is at least as big as the specified length, and which can lock up ...

8. ByteBuffer from OutputStream

In Java I need to put content of OutputStream (I fill data to that stream myself) into a ByteBuffer. How to do it in a simple way ?

9. compare ByteBuffer contents?

What's the easiest way in Java to compare the contents of two ByteBuffers to check for equality?

10. Open source C implementation of Java ByteBuffer and Double Byte Char String

Can someone point me to an open-source C implementation of: a. ByteBuffer similar to the one in Java, and b. DBCS. I am a starter in this area and desperately need some help. Thanks ...

11. java memcopy DirectBuffer

Hi I am working with direct buffers in Java, and I need to have a fast memcopy on them. In C there is the memcpy command, and on Java Arrays I ...

12. Is there similar java ByteBuffer function to pointer function in C

I am using ByteBuffer to transfer data with java nio. A same message can be sent to multiple receivers. The message format is "message header + message content". A staright way ...

13. How do you get successive slices out of a ByteBuffer?

I have a ByteBuffer that contains a large file (100 MB):

    java.nio.ByteBuffer byteBuffer = ByteBuffer.wrap(multipartFile.getBytes());
I can only legally ...

14. Are Java DirectByteBuffer wrappers garbage collected?

I understand that when a directbytebuffer is allocated, its not subject to garbage collection, but what I'm wondering is if the wrapping object is garbage collected. For example, if I allocated a ...

15. How do I determine MaxDirectMemorySize on a running JVM?

I have an application which uses DirectByteBuffers to store data, but I'd like to know what MaxDirectMemorySize is so I don't accidentally exceed it. Without configuring this manually, how can I figure ...

16. Javolution ByteBuffer question

I have the following implementation with Javolution:

public class RunScan extends Struct
    public final Signed32 numOfClusters = new Signed32();
    public final ClusterData[] clusters;

17. Expandable ByteBuffer equivalent supporting little endian write/reads?

I'm currently using a ByteBuffer to store a chain of primitives before sending it all over the wire. I'm using data.order(ByteOrder.LITTLE_ENDIAN); because that's how data should be sent. Is there a ByteBuffer ...

18. I/O Operation On Channels Using ByteBuffer - Performance Comparision

I want to perform I/O operation on channels using ByteBuffer. Finally I came up with three solutions:

FileChannel inChannel = new FileInputStream("input.txt").getChannel();
FileChannel outChannel = new FileOutputStream("output.txt").getChannel();
ByteBuffer buf = ByteBuffer.allocate(1024 * 1024);
Method 1: ...

19. ByteBuffer api giving wrong integer values

I am using ByteBuffer APIs to convert an object into bytes. The object's class is as follows

public class Obj{
int a; // size 1 byte
int b; // size 4 bytes
int c; // ...

20. Java : Extending from ByteBuffer

Java will not allow me to extend from ByteBuffer because it implements abstract methods that I am not overriding, yet these methods work for any ByteBuffer objects that are created, such ...

21. Switch Compile Error

I've looked at other questions and still can't figure it out. Why won't it let me compile this code with a switch statement? I get error that typical error "case ...

22. To big byte ? How can i solved it?

i created webserver in java, and i have client in javascript, when i send ms from client to server i get this error:

    at Source)
at Source)
at ...

23. ByteBuffer optional methods

Optional methods are found in many classes in the standard APIs. If you attempt to invoke an optional method using an instance that does not support it, an UnsupportedOperationException is thrown. How do you know if an instance supports a given method? This depends on the class, but generally it's determined by how the instance was created. You can consult the ...

25. method ByteBuffer.rewind()

reading thru "thinking in java, 3rd ed." by bruce eckel, i came across this code in the New I/O topic, section on Converting data: code: ...... ByteBuffer buff=ByteBuffer.allocate(1024); ..... buff.rewind(); i have checked the java API and i could not find the method ByteBuffer.rewind().please, can anyone help me with the function of this method. akoma henry

26. ByteBuffer

I am not getting this flip business in NIO buffer. I am trying to use ByteBuffer as circular buffer. Now After I read 20 bytes into ByteBuffer, I only want to get 10 bytes from bytes and then continue reading. But problem is that when I have to get the 10 bytes I flip the buffer, position is set to 0, ...

27. Can I use ByteBuffer and InputStream together?

There's some existing code that reads in a file, creating a ByteBuffer from file's byte[]. The ByteOrder is set to LITTLE_ENDIAN and getInt correctly gets the expected header constants from the file, etc. Everything works. I'd like to change this because we end up having to instantiate a byte[] for the whole file this way. I'd like to open a stream ...

28. inputstream to bytebuffer

I have an inputstream that I need to read the data into a byte array or a byter buffer. The problem is I don't know exactly how many bytes I need to read into array to wrap with the bytebuffer. Any help reading an inputstream to a byte array without any indication of how many bytes there are that would be ...

29. The ByteBuffer Class in Java

30. ByteBuffer

hello everone, well first of i am new to java and i dont have much working experinence of java, well i am little bit confused with how ByteBuffer exactly works because from java documentaion i came know that when a call to allocate()/allocateDirect() happens the initial order of a byte buffer is always BIG_ENDIAN. But as i see very occassionaly i ...

31. Reading Characters from a ByteBuffer

32. abstract methods in ByteBuffer class

Yeah, it's a subclass of ByteBuffer. You can find out more about the class by using introspection. But, you don't have to, to use this API. This is called "design-by-contract" (well, part of it anyway), and that's why the class is hidden with respect to the API docs. The idea is that an API is kind of like a contract, an ...

33. Using an Abstract Class : ByteBuffer

Aliens? Oh I only wish it had been aliens. They were Bureaucrats! It was horrible! I think I understand your exmaple with the interface fairly clearly. I can see why object created by FooFactor is not, in fact an IFOO but something that just follows the interface defined by IFOO. That was very clear thank you. Let me ask a follow ...

34. ByteBuffer Question

ByteBuffers aren't meant for this kind of operation. If you need to do it with a ByteBuffer, allocate a new ByteBuffer the size of the old one plus the size of the input you want to insert, then copy from the old to the new up to the index you want to insert, then copy the new data at the index, ...

35. Extending ByteBuffer

The problem is that I need the full functionality of the ByteBuffer, and only some minor changes in wrap(byte[], int, int), flip() and compact(). The rest I need it to stay the same, and of course I do not want to encapsulate the whole funationality of a ByteBuffer into a new object.

36. ByteBuffer question

It looks like you have a "pdfContent" variable which is a String. Or something else which has a getBytes(String) method, but I'm going to go with my String guess at the moment. I'm not sure why it's called that, because PDF isn't a text format. So I'm not going to guess any more about what that code was really supposed to ...

37. ByteBuffer.allocateDirect() behaviour intentional?

As you can see in [another forum post|] I use ByteBuffer.allocateDirect() to allocate memory to avoid the heap size restrictions, as this allows me to work around the restrictions so that I can store an entire Ogg stream in my applet. I want to know if it is an intentional behavior by the security manager to allow this to "slip through" ...

38. ByteBuffer - creating strings

What happens if you use the ByteBuffer get method which takes an array (you're using the method which takes an array, an offset into the array, and the number of bytes to read)? Using in.get(word, 0, i-j), which does let you hoist the array creation out of the loop, is an optimisation. Use the simpler one first to get it working. ...

39. A question about ByteBuffer?

40. Need to put contents of a file stored in FileContents into a ByteBuffer

That's all the spoon feeding I needed. Minus the DataInputStream, I was dead on with my final "guess" before the previous reply. DataInputStream was what i needed to complete the puzzle. Here's the final code (simple enough): int length = new Long(fileContents.getLength()).intValue(); byte bytes[] = new byte[length]; InputStream file = fileContents.getInputStream(); DataInputStream dis = new DataInputStream(file); dis.readFully(bytes); ByteBuffer buf = ByteBuffer.wrap(bytes); ...

41. Reading contents of a ByteBuffer

42. ByteBuffer trouble

43. How to read the Bytes from a ByteBuffer ?

Hi, you are right, the numbers are all squished. But they aren't the expected numbers... I expect to print the binary representation from my Bytebuffer. I stored a float into a ByteBuffer, so that the float would be convert in Byte. And I try to show the Bytes which are into the ByteBuffer. Thx Stan

44. Why do ByteBuffer.wrap() and ByteBuffer.slice() have the same behavior

But I would think that slice().array() would yield the sliced array and not the entire backing array, otherwise there isn't too much functional difference between ByteBuffer.wrap() and ByteBuffer.slice(). I guess there is no way to say that the behavior is a Java implementation error but (to me) it just doesn't make much sense. As they say, "Oh Well". thanks  | Contact Us | Privacy Policy
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