Linux at my work

1. I had a situation where there was a variable by name "production.variable" being used in a java file, but i wanted to know where it is being used apart from this java file, i have multiple folders under which there were many java files and XML files, now how to find which of these files use production.variable"

ANS : grep production.variable -R *
[OR]
grep 'some strings with spaces' -R *