14.18

The

try

 statement

BLOCKS AND STATEMENTS

14.18   The

try

 statement

These are the times that try men's souls.

Thomas Paine

, The American Crisis

(1780)

. . . and they all fell to playing the game of catch as catch can,

till the gunpowder ran out at the heels of their boots.

Samuel Foote

A

try

 statement executes a block. If a value is thrown and the

try

 statement has

one or more

catch

 clauses that can catch it, then control will be transferred to the

first such

catch

 clause. If the

try

 statement has a

finally

 clause, then another

block of code is executed, no matter whether the

try

 block completes normally or

abruptly, and no matter whether a

catch

 clause is first given control.

TryStatement:

try

Block Catches

try

Block Catches

opt

Finally

Catches:

CatchClause

Catches CatchClause

CatchClause:

catch (

FormalParameter

 )

Block

Finally:

finally

Block

The following is repeated from  8.4.1 to make the presentation here clearer:

FormalParameter:

Type VariableDeclaratorId

The following is repeated from  8.3 to make the presentation here clearer:

VariableDeclaratorId:

Identifier

VariableDeclaratorId

 [ ]

The

Block

 immediately after the keyword

try

 is called the

try

 block of the

try

 statement. The

Block

 immediately after the keyword

finally

 is called the

finally

 block of the

try

 statement.

A

try

 statement may have

catch

 clauses (also called

exception handlers

).

A

catch

 clause must have exactly one parameter (which is called an

exception

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