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This compliant solution avoids the TOCTOU vulnerability by copying the mutable input and then perform performing all operations on the copy. Consequently, an attacker's changes to the mutable input cannot affect the copy. Acceptable techniques include using a copy constructor or implementing the java.lang.Cloneable interface and declaring a public clone method (for classes not declared as final). In cases where the mutable class is declared final — that is, it cannot provide an accessible copy method — perform a manual copy of the object state within the caller. See guideline OBJ08-J. Provide mutable classes with copy functionality to allow passing instances to untrusted code safely for more information. Note that any input validation must be performed on the copy and not on the original object.
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