title: Inserting magic number into class files
body: <p>I have a jar in which all of the class files have their magic number and type removed, I am not very knowledgeable about this specific area.  What would be the best way to go about adding back in 0XCAFEBABE and the type back into each classfile and repacking the jar?</p>
  
  <p>EDIT: i have checked, only the magic number is missing, the files are intact if i add it manually.</p>