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The guideline CON04-J. Synchronize using an internal private final lock object recommends documenting the locking strategy of classes designed for inheritance. This information is useful for deciding the locking strategy of subclasses.
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This compliant solution does not violate CON04-J. Synchronize using an internal private final lock object because the accessibility of the class is package-private which is allowable when untrusted code cannot infiltrate the package.
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This noncompliant code example defines a doSomething() method in class Base that uses an internal private lock, in accordance with CON04-J. Synchronize using an internal private final lock object.
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