From Fedora Project Wiki
Proposed modification to the Java Packaging Guideline
Currently the sample Ant spec file in the Java packaging guidelines includes the command
find -name '*.jar' -o -name '*.class' -exec rm -f '{}' \;
for cleansing pre-existing binary files. However, the command is incorrect, as it does not clean out .jar files. I propose the command to read either
find \( -name '*.jar' -o -name '*.class' \) -exec rm -f '{}' \;
or
find -name '*.class' -exec rm -f '{}' \; find -name '*.jar' -exec rm -f '{}' \;
both of which perform the operation correctly.