Rethrowing exceptions in Java without losing the stack trace

Question

In C#, I can use the throw; statement to rethrow an exception while preserving the stack trace:

try
{
   ...
}
catch (Exception e)
{
   if (e is         


        

Answer 1

I would prefer:

try
{
    ...
}
catch (FooException fe){
   throw fe;
}
catch (Exception e)
{
    // Note: don't catch all exceptions like this unless you know what you
    // are doing.
    ...
}

Answer 2

something like this

try 
{
  ...
}
catch (FooException e) 
{
  throw e;
}
catch (Exception e)
{
  ...
}

Answer 3

public int read(byte[] a) throws IOException {
    try {
        return in.read(a);
    } catch (final Throwable t) {
        /* can do something here, like  in=null;  */
        throw t;
    }
}

This is a concrete example where the method throws an IOException. The final means t can only hold an exception thrown from the try block. Additional reading material can be found here and here.

Answer 4

You can also wrap the exception in another one AND keep the original stack trace by passing in the Exception as a Throwable as the cause parameter:

try
{
   ...
}
catch (Exception e)
{
     throw new YourOwnException(e);
}

Answer 5

Stack trace is prserved if you wrap the catched excetion into an other exception (to provide more info) or if you just rethrow the catched excetion.

try{ ... }catch (FooException e){ throw new BarException("Some usefull info", e); }

Answer 6

In Java is almost the same:

try
{
   ...
}
catch (Exception e)
{
   if (e instanceof FooException)
     throw e;
}