What's the Difference Between `throw` and `throw new Exception()` in Exception Handling?

In-depth understanding of the difference between throw and throw new Exception()

In

exception handling, there is a significant difference in the usage effects of throw and throw new Exception(). Let’s dive into their respective behaviors:

throw: Keep original exception information

The

throw statement rethrows the currently active exception. When used within a catch block, it retains the original exception's type, message, and stack trace. This allows the exception to continue propagating without being modified.

<code>try { ... }
catch { throw }</code>

In this scenario, if an exception occurs in the try block, the catch block will rethrow the same exception with its original information intact.

throw new Exception(): Reset stack trace

On the other hand, throw new Exception(message)creates a new exception instance with the specified message. This action resets the stack trace, removing all tracing information that occurred before the catch block.

<code>try{ ... }
catch(Exception e) {throw new Exception(e.message) }</code>

In this example, if an exception occurs in the try block, the catch block will create a new exception with the message of the original exception, but the stack trace starts from the catch block itself.

Avoid using throw ex

It is strongly recommended not to use catch within a throw ex block. Doing so causes the original exception to be propagated, but the stack trace is reset. This makes debugging the source of the exception very difficult.

Create custom exception

In some cases it may be necessary to wrap all exceptions in a custom exception object to provide additional information. To do this, define a new exception class that inherits from Exception, including all four exception constructors. Optionally, you can add an additional constructor that accepts the original exception and additional information. When throwing a custom exception, be sure to pass the original exception as an inner exception parameter to preserve its stack trace and other properties.

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