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.