Specify argument nullability.

import java.math.BigDecimal;

import java.util.Locale;

import javax.annotation.Nonnull;

import javax.annotation.Nullable;

public class DictionaryStats {

    public static final int NOT_AN_ENTRY_COUNT = -1;

    public final long mDictFileSize;

    public final int mContentVersion;

    public DictionaryStats(final Locale locale, final String dictType, final String dictFileName,

            final File dictFile, final int contentVersion) {

    public DictionaryStats(

            @Nonnull final Locale locale,

            @Nonnull final String dictType,

            @Nonnull final String dictFileName,

            @Nullable final File dictFile,

            final int contentVersion) {

        mLocale = locale;

        mDictType = dictType;

        mDictFileSize = (dictFile == null || !dictFile.exists()) ? 0 : dictFile.length();

    }

    public String getFileSizeString() {

        if (mDictFileSize == 0) {

            return "0";

        }

        BigDecimal bytes = new BigDecimal(mDictFileSize);

        BigDecimal kb = bytes.divide(new BigDecimal(1024), 2, BigDecimal.ROUND_HALF_UP);

        if (kb.longValue() == 0) {