.jrubyrc

# Example of .jrubyrc

# Set compilation mode. JIT = at runtime; FORCE = before execution. (JIT, FORCE, OFF, OFFIR)
# compile.mode = FORCE

# Dump to console all bytecode generated at runtime.
# compile.dump = true

# Enable verbose JIT logging (reports failed compilation)
# jit.logging.verbose = true

# Log require/load file searches.
# debug.loadService = true

# Display location of the file executed with the -S option
# debug.scriptResolution = true

compat.version = 1.9

# Set the style of exception backtraces. (normal, raw, full, mri)
backtrace.style = raw
# Enable colorized backtraces.
backtrace.color = true 

gistfile1.txt

Alternatives:

* export JRUBY_OPTS=--1.9 to .rvmrc

* chmod +x ${rvm_path}/hooks/after_use_jruby_opts # or after_use_jruby