The Java Language Specification, Third Edition

BLOCKS AND STATEMENTS Expression Statements 14.8
A labeled statement is executed by executing the immediately contained
Statement. If the statement is labeled by an Identifier and the contained Statement
completes abruptly because of a break with the same Identifier, then the labeled
statement completes normally. In all other cases of abrupt completion of the
Statement, the labeled statement completes abruptly for the same reason.
14.8 Expression Statements
Certain kinds of expressions may be used as statements by following them with
semicolons:
ExpressionStatement:
StatementExpression ;
StatementExpression:
Assignment
PreIncrementExpression
PreDecrementExpression
PostIncrementExpression
PostDecrementExpression
MethodInvocation
ClassInstanceCreationExpression
An expression statement is executed by evaluating the expression; if the
expression has a value, the value is discarded. Execution of the expression statement
completes normally if and only if evaluation of the expression completes
normally.
Unlike C and C++, the Java programming language allows only certain forms
of expressions to be used as expression statements. Note that the Java programming
language does not allow a “cast to void”—void is not a type—so the traditional
C trick of writing an expression statement such as:
(void) ... ;// incorrect!
does not work. On the other hand, the language allows all the most useful kinds of
expressions in expressions statements, and it does not require a method invocation
used as an expression statement to invoke a void method, so such a trick is almost
never needed. If a trick is needed, either an assignment statement (§15.26) or a
local variable declaration statement (§14.4) can be used instead.
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