JLS myths ~ if-then-else statement ~

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JLS myths ~ if-then-else statement ~ HASUNUMA Kenji k.hasunuma@coppermine.jp GlassFish Users Group Japan

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if-else statement if ( someObject.eval() ) if ( otherObject.eval() ) func1(); else func2(); assume that someObject.eval() is false. which is run, func1 or func2?

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if-else statement if ( someObject.eval() ) if ( otherObject.eval() ) func1(); else func2(); assume that someObject.eval() is false. Neither func1 nor func2 is run.

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if-else statement if ( someObject.eval() ) if ( otherObject.eval() ) func1(); else func2(); It's if-else's short-circuit. Don't be misled by source code format!

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From JLS (Java SE 8) IfThenStatement: if ( Expression ) Statement IfThenElseStatement: if ( Expression ) StatementNoShortIf else Statement IfThenElseStatementNoShortIf: if ( Expression ) StatementNoShortIf else StatementNoShortIf

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Statement Statement: StatementWithoutTrailingSubstatement LabeledStatement IfThenStatement IfThenElseStatement WhileStatement ForStatement

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StatementNoShortIf StatementNoShortIf: StatementWithoutTrailingSubstatement LabeledStatementNoShortIf IfThenElseStatementNoShortIf WhileStatementNoShortIf ForStatementNoShortIf *** 'IfThenStatementNoShortIf' don't exist ***

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if-else statement (ﬁxed) if ( someObject.eval() ) { if ( otherObject.eval() ) func1(); } else func2(); assume that someObject.eval() is false. which is run, func1 or func2?

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if-else statement (ﬁxed) if ( someObject.eval() ) { if ( otherObject.eval() ) func1(); } else func2(); func2 is run! because it use block as statement in outer if statement

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JLS myths ~ If-then-else statement ~ HASUNUMA Kenji k.hasunuma@coppermine.jp GlassFish Users Group Japan