Strange behavior with JRuby IO#rewind when backed by a ByteArrayInputStream

gistfile1.rb

# https://github.com/jruby/jruby/blob/master/src/org/jruby/RubyIO.java
#
# public RubyFixnum rewind (...) {
#   calls OpenFile#getMainStreamSafe#lseek(0L, Stream.SEEK_SET)
#
# https://github.com/jruby/jruby/blob/master/src/org/jruby/util/io/ChannelStream.java
#
# public synchronized void lseek (...) {
#   checks if the fd is seekable
#   checks if the fd is a SelectableChannel
#   if not, drops out the bottom silently

require 'java'
java_import java.io.ByteArrayInputStream

java_input_stream = ByteArrayInputStream.new((1..100).to_a.to_java(:byte))
ruby_input_stream = java_input_stream.to_io

data = ruby_input_stream.read
puts "data size before rewind: #{data.size}"

ruby_input_stream.rewind

data = ruby_input_stream.read
puts "data size after rewind: #{data.size}"

# ➜  jruby-bug  rvm use jruby-1.5.6
# Using /Users/jdc/.rvm/gems/jruby-1.5.6
# ➜  jruby-bug  ruby bug.rb
# data size before rewind: 100
# data size after rewind: 0

# ➜  jruby-bug  rvm use jruby-1.6.2
# Using /Users/jdc/.rvm/gems/jruby-1.6.2
# ➜  jruby-bug  ruby bug.rb
# data size before rewind: 100
# data size after rewind: 0