presto-main/src/main/java/io/prestosql/operator/scalar/MultimapFromEntriesFunction.java/MultimapFromEntriesFunction/initializeEntryIndicesList
class MultimapFromEntriesFunction:    private void initializeEntryIndicesList(int entryCount)
    {
        entryIndicesList = new IntList[entryCount];
        for (int i = 0; i < entryIndicesList.length; i++) {
            entryIndicesList[i] = new IntArrayList();
        }
    }