Strings in Switch .. and classes

[Paul Benedict]

It occurred to me that if hashCode() really is an acceptable and
fool-proof (yet to be convinced) way to implement strings in switch,
this potentially opens a further enhancement to switch on Class.
Perhaps in JDK 8, we could convert many instanceof checks into label
cases.

Class c = o.getClass();
if (c instanceof String) {  .. }
else if (c instanceof Integer) { ..}
else if (c instanceof Date) { .. }

Can be de-sugared into the new String switch:

switch (object.getClass().getName()) {
  case "java.lang.String":
  case "java.lang.Integer":
  case "java.util.Date":
  }
}

PS: Since instanceof evaluates null to false, as like any other switch
statement, an if-check should still be done in front lest an NPE
occurs.

Paul