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Catching an exception and throwing another is a common pattern. This is often
used to supply additional information, or to turn a checked exception into an
unchecked one.
```java
try {
ioLogic();
} catch (IOException e) {
throw new IllegalStateException(); // BAD
}
```
Throwing a new exception without supplying the caught one as a cause means the
stack trace will terminate at the `catch` block, which will make debugging a
possible fault in `ioLogic()` far harder than is necessary.
Prefer wrapping the original exception instead,
```java
try {
ioLogic();
} catch (IOException e) {
throw new IllegalStateException(e); // GOOD
}
```
## Suppression
If the exception is deliberately unused, rename it `unused` to suppress this
diagnostic.
```java
static <T extends Enum<T>> T tryForName(Class<T> enumType, String name) {
try {
return Enum.valueOf(enumType, name);
} catch (IllegalArgumentException unused) {
return null;
}
}
```
Otherwise, suppress false positives with `@SuppressWarnings("UnusedException")`
on the ignored exception. Consider also adding a comment to explain why the
exception should not be propagated.
```java
try {
...
} catch (@SuppressWarnings("UnusedException") IOException e) {
throw new IllegalStateException();
}
```
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