code: private void readRequiredJarFiles(final DataInput in) throws IOException {
  
  		// Do jar files follow;
  		final int numJars = in.readInt();
  
  		if (numJars > 0) {
  
  			for (int i = 0; i < numJars; i++) {
  
  				final Path p = new Path();
  				p.read(in);
  				this.userJars.add(p);
  
  				// Read the size of the jar file
  				final long sizeOfJar = in.readLong();
  
  				// Add the jar to the library manager
  				LibraryCacheManager.addLibrary(this.jobID, p, sizeOfJar, in);
  			}
  
  		}
  
  		// Register this job with the library cache manager
  		LibraryCacheManager.register(this.jobID, this.userJars.toArray(new Path[0]));
  	}
docs: Reads required JAR files from an input stream and adds them to the
  library cache manager.
  
  @param in
  the data stream to read the JAR files from
  @throws IOException
  thrown if an error occurs while reading the stream