Declaring shared variables as volatile ensures visibility and limits reordering of accesses. Volatile accesses do not guarantee the atomicity of composite operations such as incrementing a variable (CON01-J. Design APIs that ensure atomicity of composite operations and visibility of resultsDo not assume all primitive operators are atomic).
Declaring variables as volatile establishes a happens-before relationship such that a write to the volatile variable is always seen by a subsequent read. Statements that occur before the write to the volatile field also happen-before the read of the volatile field.
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The use of the volatile keyword is inappropriate for composite operations on shared variables (CON01-J. Design APIs that ensure atomicity of composite operations and visibility of resultsDo not assume all primitive operators are atomic).
Noncompliant Code Example (visibility)
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