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Asked: 2026-05-22T12:12:32+00:00

I just found there is no readUnsignedInt () method in the RandomAccessFile class. Why?

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I just found there is no readUnsignedInt() method in the RandomAccessFile class. Why? Is there any workaround to read an unsigned int out from the file?

Edit:

I want to read an unsigned int from file and put it into a long space.

Edit2:

Cannot use readLong(). it will read 8 bytes not 4 bytes. the data in the file have unsigned ints in 4 bytes range.

Edit3:

Found answer here: http://www.petefreitag.com/item/183.cfm

Edit4:

how about if the data file is little-endian? we need to bits swap first?

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1 Answer

  1. Editorial Team

    I’d do it like this:

    long l = file.readInt() & 0xFFFFFFFFL;

    The bit operation is necessary because the upcast will extend a negative sign.

    Concerning the endianness. To the best of my knowledge all I/O in Java is done in big endian fashion. Of course, often it doesn’t matter (byte arrays, UTF-8 encoding, etc. are not affected by endianness) but many methods of DataInput are. If your number is stored in little endian, you have to convert it yourself. The only facility in standard Java I know of that allows configuration of endianness is ByteBuffer via the order() method but then you open the gate to NIO and I don’t have a lot of experience with that.

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