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    <p>All this amounts to exploiting the loophole that an unchecked cast to a generic type is not a compiler error. Your code is explicitly made type-unsafe if it contains such an expression. And since the checking of checked exceptions is strictly a compile-time procedure, nothing will break in the runtime.</p> <p>The answer from the authors of Generics would most probably be along the lines of "If you are using unchecked casts, it's your problem".</p> <p>I see something quite positive in your discovery&mdash;a break out of the stronghold of checked exceptions. Unfortunately, this can't turn existing checked-exception-poisoned APIs into something more pleasant to use.</p> <h2>How this can help</h2> <p>At a typical layered application project of mine there will be a lot of boilerplate like this:</p> <pre><code>try { ... business logic stuff ... } catch (RuntimeException e) { throw e; } catch (Exception e) { throw new RuntimeException(e); } </code></pre> <p>Why do I do it? Simple: there are no business-value exceptions to catch; any exception is a symptom of a runtime error. The exception must be propagated up the call stack towards the global exception barrier. With Lukas' fine contribution I can now write</p> <pre><code>try { ... business logic stuff ... } catch (Exception e) { throwUnchecked(e); } </code></pre> <p>This may not seem like much, but the benefits accumulate after repeating it 100 times throughout the project.</p> <h2>Disclaimer</h2> <p>In my projects there is high discipline regarding exceptions so this is a nice fit for them. <strong>This kind of trickery is not something to adopt as a general coding principle</strong>. Wrapping the exception is still the only safe option in many cases.</p>
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    1. POWhat parts of the JLS justify being able to throw checked exceptions as if they were unchecked?
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    1. USMarko Topolnik
    1. USMarko Topolnik
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    1. CO*"checked-exception-poisoned APIs"* ;-)
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    2. COThat can thoroughly break callers who expect checked exceptions to be declared. Imagine a try block containing multiple invocations. One of the methods called declares `throws FooException`, another does not but throws it anyways. A catch block handling `FooException` might not expect the state the program is in when that comes to pass.
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    3. CO@Ben I agree, this is definitely not to be seen as a general recommendation. First of all, it helps only when you are authoring code that throws the exception, and in that case you should just choose an unchecked exception to throw.
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