Is the structure for a jar file for running Spark applications the same as that for Hadoop

[Steve Lewis]

 In a Hadoop jar there is a directory called lib and all non-provided third
party jars go there and are included in the class path of the code. Do jars
for Spark have the same structure - another way to ask the question is if I
have code to execute Spark and a jar build for Hadoop can I simply use that
jar?