BLOCKS AND STATEMENTS

The

break

 Statement

14.13

14.13   The

break

 Statement

A break statement transfers control out of an enclosing statement.

BreakStatement:

break

Identifier

opt

 ;

A

break

 statement with no label attempts to transfer control to the innermost

enclosing

switch

,

while

,

do

, or

for

 statement; this statement, which is called the

break target

, then immediately completes normally. To be precise, a

break

 state 

ment with no label always completes abruptly, the reason being a

break

 with no

label. If no

switch

,

while

,

do

, or

for

 statement encloses the

break

 statement, a

compile time error occurs.

A

break

 statement with label

Identifier

 attempts to transfer control to the

enclosing labeled statement ( 14.6) that has the same

Identifier

 as its label; this

statement, which is called the

break target

, then immediately completes normally.

In this case, the

break

 target need not be a

while

,

do

,

for

, or

switch

 statement.

To be precise, a

break

 statement with label

Identifier

 always completes abruptly,

the reason being a

break

 with label

Identifier

. If no labeled statement with

Identifier

as its label encloses the

break

 statement, a compile time error occurs.

It can be seen, then, that a

break

 statement always completes abruptly.

The preceding descriptions say  attempts to transfer control  rather than just

 transfers control  because if there are any

try

 statements ( 14.18) within the

break target whose

try

 blocks contain the

break

 statement, then any

finally

clauses of those

try

 statements are executed, in order, innermost to outermost,

before control is transferred to the break target. Abrupt completion of a

finally

clause can disrupt the transfer of control initiated by a

break

 statement.

In the following example, a mathematical graph is represented by an array of

arrays. A graph consists of a set of nodes and a set of edges; each edge is an arrow

that points from some node to some other node, or from a node to itself. In this

example it is assumed that there are no redundant edges; that is, for any two nodes

P

 and

Q

, where

Q

 may be the same as

P

, there is at most one edge from

P

 to

Q

.

Nodes are represented by integers, and there is an edge from node

i

 to node

edges[i ][j ]

 for every

i

 and

j

 for which the array reference

edges[i ][j ]

does not throw an

IndexOutOfBoundsException

.

The task of the method

loseEdges

, given integers

i

 and

j

, is to construct a

new graph by copying a given graph but omitting the edge from node

i

 to node

j

,

if any, and the edge from node

j

 to node

i

, if any:

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