8073550: java* tools: replace obj.getClass hacks with Assert.checkNonNull or Objects.requireNonNull
Summary: replace getClass() with approapriate NPE checks
Reviewed-by: jjg
Contributed-by: aleksey.shipilev@oracle.com

8054834: Modular Source Code
Reviewed-by: alanb, chegar, ihse, mduigou
Contributed-by: alan.bateman@oracle.com, alex.buckley@oracle.com, chris.hegarty@oracle.com, erik.joelsson@oracle.com, jonathan.gibbons@oracle.com, karen.kinnear@oracle.com, magnus.ihse.bursie@oracle.com, mandy.chung@oracle.com, mark.reinhold@oracle.com, paul.sandoz@oracle.com