FULL PRODUCT VERSION :
java version "1.8.0_151"
Java(TM) SE Runtime Environment (build 1.8.0_151-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.151-b12, mixed mode)
(but seems to have been there since at least Java 6)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 6.1.7601]

A DESCRIPTION OF THE PROBLEM :
In a nested try-catch an unreachable catch block is sometimes not found, it depends on the throws declaration in the exception throwing method.


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
public class Buggy
{
   // comment out one of those two lines
   private void thrower() throws Exception
   //private void thrower() throws SQLException
   {
      // some code so the throw may occur
      throw new SQLException();
   }

   private void tester()
   {
      try
      {
         try
         {
            thrower();
         }
         catch (SQLException s)
         { // if throwser actually throws an SQLException, it is caught here
         }
      }
      catch (SQLException s)
      { // this catch block can never be reached - that's the error - it's recognized if and only if thrower declares to throw SQLException, but no matter what thrower would actually throw or declare, this block can never be reached
      }
      catch (Exception e)
      { // maybe this will catch some RuntimeExceptions ...
      }
   }
}


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
So the outer catch-block for SQLException should always be marked as unreachable. Either an SQLException was thrown and caught in the inner catch-block for SQLException or it was not thrown.

The bug doesn't depend on SQLException, just anything derived from Exception will show this behaviour.
ACTUAL -
The outer catch-block for SQLException is marked as unreachable if and only if the thrower method declares to throw SQLException. If it declares to throw Exception the outer catch-block for SQLException is not marked as unreachable

ERROR MESSAGES/STACK TRACES THAT OCCUR :
Unreachable catch block for SQLException. This exception is never thrown from the try statement body

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
public class Buggy
{
   // comment out one of those two lines
   private void thrower() throws Exception
   //private void thrower() throws SQLException
   {
      // some code so the throw may occur
      throw new SQLException();
   }

   private void tester()
   {
      try
      {
         try
         {
            thrower();
         }
         catch (SQLException s)
         { // if throwser actually throws an SQLException, it is caught here
         }
      }
      catch (SQLException s)
      { // this catch block can never be reached - that's the error - it's recognized if and only if thrower declares to throw SQLException, but no matter what thrower would actually throw or declare, this block can never be reached
      }
      catch (Exception e)
      { // maybe this will catch some RuntimeExceptions ...
      }
   }
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Remove the unreachable code - if found as unreachable.

The problem is when the throwing code comes from a library throwing SQLException and some others, the outer catch-block for SQLException won't be recognized as unreachable code.