Error when write.xlsx and row.names is set to FALSE

What steps will reproduce the problem?

The chunk of code below works appropriately with the first data frame. However, 
it chokes with the second one manipulated with dplyr.

library(dplyr)
library(xlsx)
example = read.csv('example.csv', sep = '\t')
write.xlsx(example, file = "example.xlsx", row.names = F)
example.summary = group_by(example, language) %>% summarise(texts = n(), tokens 
= sum(words))
write.xlsx(example.summary, file = "example_summary.xlsx", row.names = F)

What is the expected output? What do you see instead?

I get this message

Error in .jcall(cell, "V", "setCellValue", value) : 
  method setCellValue with signature ([Ljava/lang/String;)V not found
In addition: Warning message:
In if (is.na(value)) { :
  the condition has length > 1 and only the first element will be used

What version of the product are you using? On what operating system?

R version 3.2.0 (2015-04-16) -- "Full of Ingredients"
Rstudio version 0.99.441
dplyr version 0.4.2
xlsx version 0.5.7
xlsxjars version 0.6.1
rJava 0.9-6
Mac OS X 10.10.4

Original issue reported on code.google.com by jmm...@gmail.com on 17 Jul 2015 at 1:09

Attachments:

example.csv

colearendt / xlsx

Error when write.xlsx and row.names is set to FALSE #61