有性能问题，上HeapDump性能社区

比如1.8版本的DirectByteBuffer这个类里面就有

public ByteBuffer put(byte[] src, int offset, int length) {

        if (((long)length << 0) > Bits.JNI_COPY_FROM_ARRAY_THRESHOLD) {
            checkBounds(offset, length, src.length);
            int pos = position();
            int lim = limit();
            assert (pos <= lim);
            int rem = (pos <= lim ? lim - pos : 0);
            if (length > rem)
                throw new BufferOverflowException();
                Bits.copyFromArray(src, arrayBaseOffset,
                                   (long)offset << 0,
                                   ix(pos),
                                   (long)length << 0);
            position(pos + length);
        } else {
            super.put(src, offset, length);
        }
        return this;
    }
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