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The semantics of volatile explicitly exclude any guarantee of the atomicity of compound operations that involve read-modify-write sequences such as incrementing a value (see VNA02-J. Ensure that compound operations on shared variables are atomic for more information).
Exceptions
VNA05-J-EX0: If all reads and writes of 64-bit long and double values occur within a synchronized region, the atomicity of the read/write is guaranteed. This requires both that the value is exposed only through synchronized methods in the class and that the value is inaccessible from other code (whether directly or indirectly). For more information, see VNA02-J. Ensure that compound operations on shared variables are atomic.
VNA05-J-EX1: This rule can be ignored for platforms that guarantee that 64-bit long and double values are read and written as atomic operations. Note, however, that such guarantees are not portable across different platforms.
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