Where to put finally in nested try/catch?

Question

How does finally work in nested try/catch?
E.g. for:

try{  
//code

}  
catch(SomeException e){  
   //code  
   try{  
      //code  
   }  
   catch(OtherException e){  
     //code  
   }  
}  
catch(SomeOtherException e){    
  //code  
}

Where is the best place to put finally? Or should I put it in nested and outer try as well?

It is not clear what the result should be. The `finally` block can be placed on every `try-catch`. — Uwe Plonus, Dec 12 '12 at 08:37
So if I put the `finally` in the outer `try` will it be executed?I am looking for the clearer way for this — Jim, Dec 12 '12 at 08:38

T.J. Crowder · Accepted Answer · 2012-12-12T08:44:01.133

If you want the code in the finally block to run no matter what happens in either block, put it on the outer try. If you only want it to run no matter what happens within the first try block, put it there:

try{  // try/catch #1
  //code block #1

}  
catch(SomeException e){  

   //code block #2

   try{  // try/catch #2
      //code block #3
   }  
   catch(OtherException e){  
     //code block #4
   }  
   finally {
     // This code runs no matter what happens with try/catch #2 (so
     // after code block #3 and/or #4, depending on whether there's
     // an exception). It does NOT run after code block #1 if that
     // block doesn't throw, does NOT run after code block #2 if
     // that block DOES throw), and does not run if code block #1
     // throws SomeOtherException (code block #5).
   }
}  
catch(SomeOtherException e){    
  //code block #5
} 
finally {
  // This code runs no matter what happens with EITHER
  // try/catch #1 or try/catch #2, no matter what happens
  // with any of the code blocks above, 1-5
}

More briefly:

try {
   // covered by "outer" finally
}
catch (Exception1 ex) {
   // covered by "outer" finally

   try {
     // Covered by both "inner" and "outer" finallys
   }
   catch (Exception2 ex) {
     // Covered by both "inner" and "outer" finallys
   }
   catch (Exception3 ex) {
     // Covered by both "inner" and "outer" finallys
   }
   finally { // "inner" finally
   }
}
catch (Exception4 ex) {
   // covered by "outer" finally
}
finally { // "outer" finally
}

score 3 · Answer 2 · answered Dec 12 '12 at 08:41

It depends on the place where you want the code in finally block to execute.

try{  //Try ROOT
//code

}  
catch(SomeException e){  //Catch ROOT ONE
   //code  
   try{  //Try NEST
      //code  
   }  
   catch(OtherException e){  //Catch NEST
     //code  
   }
   finally{
     //This will execute after Try NEST and Catch NEST
   }
}  
catch(SomeOtherException e){    //Catch ROOT TWO
  //code  
}
finally{
  //This will execute after try ROOT and Catch ROOT ONE and Catch ROOT TWO
}

There is no best place it's dependent on the functionality you desire. But if you want the finally block to run only after all the try catch blocks then you should place it after the final root catch block.

Where to put finally in nested try/catch?

2 Answers2