62 lines
1.9 KiB
Plaintext
62 lines
1.9 KiB
Plaintext
== Why is this an issue?
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Before it reclaims storage from an object that is no longer referenced, the garbage collector calls `finalize()` on the object.
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But there is no guarantee that this method will be called as soon as the last references to the object are removed.
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It can be few microseconds to few minutes later.
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For this reason relying on overriding the `finalize()` method to release resources or to update the state of the program is highly discouraged.
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=== What is the potential impact?
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More unexpected issues can be caused by relying on the `finalize()` method to perform important operations on the application state:
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* The JVM might terminate without ever calling this method on a particular object, leaving an unexpected or incomplete state of the program
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* Uncaught exceptions will be ignored inside this method, making it harder to detect issues that could have been logged otherwise
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* Finalizer methods can also be invoked concurrently, even on single-threaded applications, making it hard to maintain desired program invariants
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=== Noncompliant code example
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[source,java]
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----
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public class MyClass {
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@Override
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protected void finalize() { // Noncompliant
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releaseSomeResources();
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}
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}
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----
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=== Exceptions
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It is allowed to override the `finalize()` method as `final` method with an empty body, to prevent the _finalizer attack_ as described in _MET12-J-EX1_.
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== Resources
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* https://docs.oracle.com/javase/specs/jls/se17/html/jls-12.html#jls-12.6[docs.oracle.com] - Finalization of Class Instances
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* https://wiki.sei.cmu.edu/confluence/x/4jZGBQ[CERT, MET12-J.] - Do not use finalizers
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ifdef::env-github,rspecator-view[]
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'''
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== Implementation Specification
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(visible only on this page)
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=== Message
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Do not override the "Object.finalize()" method
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'''
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== Comments And Links
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(visible only on this page)
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=== on 4 Jul 2013, 11:50:57 Freddy Mallet wrote:
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Is implemented by \http://jira.codehaus.org/browse/SONARJAVA-196
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endif::env-github,rspecator-view[]
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