rspec/rules/S2142/java/rule.adoc

== Why is this an issue?

``++InterruptedExceptions++`` should never be ignored in the code, and simply logging the exception counts in this case as "ignoring". The throwing of the ``++InterruptedException++`` clears the interrupted state of the Thread, so if the exception is not handled properly the information that the thread was interrupted will be lost. Instead, ``++InterruptedExceptions++`` should either be rethrown - immediately or after cleaning up the method's state - or the thread should be re-interrupted by calling ``++Thread.interrupt()++`` even if this is supposed to be a single-threaded application. Any other course of action risks delaying thread shutdown and loses the information that the thread was interrupted - probably without finishing its task.


Similarly, the ``++ThreadDeath++`` exception should also be propagated. According to its JavaDoc:

____
If ``++ThreadDeath++`` is caught by a method, it is important that it be rethrown so that the thread actually dies.

____


=== Noncompliant code example

[source,java]
----
public void run () {
  try {
    while (true) { 
      // do stuff
    }
  }catch (InterruptedException e) { // Noncompliant; logging is not enough
    LOGGER.log(Level.WARN, "Interrupted!", e);
  }
}
----


=== Compliant solution

[source,java]
----
public void run () {
  try {
    while (true) { 
      // do stuff
    }
  }catch (InterruptedException e) {
    LOGGER.log(Level.WARN, "Interrupted!", e);
    // Restore interrupted state...
    Thread.currentThread().interrupt();
  }
}
----


== Resources

* https://cwe.mitre.org/data/definitions/391[MITRE, CWE-391] - Unchecked Error Condition


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