Three possible explanations:
- your default locale is incompatible with the input date - e.g. it can't understand
Sep as a month name
- there's something wrong with the input string, or
t is the wrong type (e.g. java.sql.Date instead of java.util.Date, or some other type altogether), or is not declared.
You should include details of the exception in your question to figure out which it is, but here's a working example using basically your own code, with the addition of a specific Locale.
SimpleDateFormat ft = new SimpleDateFormat("MMM dd, yyyy hh:mm:ss a", Locale.US);
java.util.Date t=ft.parse("Sep 16, 2015 10:34:23 AM");
ft.applyPattern("MM.dd");
System.out.println(ft.format(t));
output:
09.16