The following problem was originally reported in 4634068.

There are a number of classes that do not respect the
implied contract for equals and hashCode. See, for example,
Joshua Bloch's book "Effective Java", items 7-8.

javax.swing.text.SimpleAttributeSet$EmptyAttributeSet redefines
  equals(Object) but not
  hashCode()

Problems found by applying automatic tools to JDK
libraries. However, manual inspectation of the classes
reveals the same problems.

-- iag@sfbay 2002-02-06