compare ByteBuffer contents?

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

2 Answers

Alternatively, with JDK/11, there is another way of comparing a ByteBuffer with another. The API which primarily focusses on finding the mismatch between the two can be used as -

int mismatchBetweenTwoBuffers = byteBuffer1.mismatch(byteBuffer2);
if(mismatchBetweenTwoBuffers == -1) {
    System.out.println("The buffers are equal!");
} else {
    System.out.println("The buffers are mismatched at - " + mismatchBetweenTwoBuffers);
}

Its documentation reads as:-

/**
 * Finds and returns the relative index of the first mismatch between this
 * buffer and a given buffer.  The index is relative to the
 * {@link #position() position} of each buffer and will be in the range of
 * 0 (inclusive) up to the smaller of the {@link #remaining() remaining}
 * elements in each buffer (exclusive).
 *
 * <p> If the two buffers share a common prefix then the returned index is
 * the length of the common prefix and it follows that there is a mismatch
 * between the two buffers at that index within the respective buffers.
 * If one buffer is a proper prefix of the other then the returned index is
 * the smaller of the remaining elements in each buffer, and it follows that
 * the index is only valid for the buffer with the larger number of
 * remaining elements.
 * Otherwise, there is no mismatch.
 *
 * @return  The relative index of the first mismatch between this and the
 *          given buffer, otherwise -1 if no mismatch.
 *
 * @since 11
 */
public int mismatch(ByteBuffer that)
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