Solaris

jar cvf file_name.txt.jar file_name.txt

jar cvf folder_name.jar folder_name

find ./folder_name -type f ! -name "*.jar"  |xargs jar cvf a.jar

cd folder_name ; ls -l 
file1 
file2 
file3

cd folder_name ; ls -l
file1.jar
file2.jar
file3.jar

for myfile in `ls -ltr | grep -v "jar$" | awk '{print $9}'`
do
jar cvf  $myfile.jar $myfile;
rm $myfile;
done

for i in *
do
  zip $i $i 2>/dev/null && mv $i.zip $i.jar
done