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Never use return, break, continue, or throw statements within a finally block. When program execution enters a try block that has a finally block, the finally block always executes regardless of whether the try block (or any associated catch blocks) executes to normal completion. Statements that cause the finally block to complete abruptly also cause the try block to complete abruptly and consequently suppress any exception thrown from the try or catch blocks. According to the The Java Language Specification, §14.20.2, "Execution of try-finally and try-catch-finally" [JLS 20052015]:

If execution of the try block completes abruptly for any other reason R, then the finally block is executed. Then there is a choice:

  • If the finally block completes normally, then the try statement completes abruptly for reason R.
  • If the finally block completes abruptly for reason S, then the try statement completes abruptly for reason S (and reason R is discarded).

Noncompliant Code Example

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ERRO4-EX0: Control flow statements whose destination is within the finally block are perfectly acceptable. For example, the following code does not violate this rule because the break statement exits within the while loop but not within the finally block.:

Code Block
bgColor#ccccff
class TryFinally {
  private static boolean doLogic() {
    try {
      throw new IllegalStateException();
    } finally {
      int c;
      try {
        while ((c = input.read()) != -1) {
          if (c > 128) {
            break;
          }
        }
      } catch (IOException x) {
        // Forward to handler
      }
      System.out.println("logic done");
    }
    // Any return statements must go here; applicable only when exception is thrown conditionally
  }
}

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Tool
Version
Checker
Description
Coverity7.5PW.ABNORMAL_TERMINATION_ OF_FINALLY_BLOCKImplemented

Related Guidelines

MITRE CWE

CWE-459, Incomplete cleanupCleanup
CWE-584, Return inside Inside finally block Block

Bibliography

[Bloch 2005]

Puzzle 36. Indecision

[Chess 2007]

Section 8.2, "Managing Exceptions, The Vanishing Exception"

[JLS 20052015]

§14.20.2, "Execution of try-finally and try-catch-finally"

 

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