Java 6 Illuminated: An Active Learning Approach, 2nd Edition

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Do not declare the parame-

ters of a method inside the

method body. When the

method begins executing,

the parameters exist and

have been assigned the

values set by the client in

the method call.

COMMON ERROR

TRAP

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Be aware that a method

parameter or local variable

that has the same name as

an instance variable hides

the instance variable.

COMMON ERROR

TRAP

7.7 Writing Data Manipulation Methods 393

for the parameter. To avoid name conflicts, we name each parameter using the

pattern newInstanceVariable.

A similar common error is to declare a local variable with the same name as

the instance variable, as shown in the following incorrectly coded method:

// Incorrect! ...