The Java Language Specification, Third Edition

BLOCKS AND STATEMENTS Unreachable Statements 14.21
• A break, continue, return, or throw statement cannot complete normally.
• A synchronized statement can complete normally iff the contained statement
can complete normally. The contained statement is reachable iff the
synchronized statement is reachable.
• A try statement can complete normally iff both of the following are true:
◆ The try block can complete normally or any catch block can complete
normally.
◆ If the try statement has a finally block, then the finally block can complete
normally.
• The try block is reachable iff the try statement is reachable.
• A catch block C is reachable iff both of the following are true:
◆ Some expression or throw statement in the try block is reachable and can
throw an exception whose type is assignable to the parameter of the catch
clause C. (An expression is considered reachable iff the innermost statement
containing it is reachable.)
◆ There is no earlier catch block A in the try statement such that the type of
C’s parameter is the same as or a subclass of the type of A’s parameter.
• If a finally block is present, it is reachable iff the try statement is reachable.
One might expect the if statement to be handled in the following manner, but
these are not the rules that the Java programming language actually uses:
• HYPOTHETICAL: An if–then statement can complete normally iff at least
one of the following is true:
◆ The if–then statement is reachable and the condition expression is not a
constant expression whose value is true.
DRAFT
◆ The then–statement can complete normally.
• The then–statement is reachable iff the if–then statement is reachable and
the condition expression is not a constant expression whose value is false.
• HYPOTHETICAL: An if–then–else statement can complete normally iff
the then–statement can complete normally or the else–statement can complete
normally. The then-statement is reachable iff the if–then–else statement
is reachable and the condition expression is not a constant expression
whose value is false. The else statement is reachable iff the if–then–else
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