20.12

java.lang.String

THE PACKAGE JAVA.LANG

20.12.33

public String concat(String str)

throws NullPointerException

If the length of the argument string is zero, then a reference to this

String

 object

is returned. Otherwise, a new

String

 object is created, representing a character

sequence that is the concatenation of the character sequence represented by this

String

 object and the character sequence represented by the argument string.

Examples:

"cares".concat("s")

returns

 "caress"

"to".concat("get").concat("her")

returns

 "together"

If

str

 is

null

, a

NullPointerException

 is thrown.

20.12.34

public String replace(char oldChar, char newChar)

If the character

oldChar

 does not occur in the character sequence represented by

this

String

 object, then a reference to this

String

 object is returned. Otherwise,

a new

String

 object is created that represents a character sequence identical to

the character sequence represented by this

String

 object, except that every occur 

rence of

oldChar

 is replaced by an occurrence of

newChar

.

Examples:

"mesquite in your cellar".replace( e ,  o )

returns

 "mosquito in your collar"

"the war of baronets".replace( r ,  y )

returns

 "the way of bayonets"

"sparring with a purple porpoise".replace( p ,  t )

returns

 "starring with a turtle tortoise"

"JonL".replace( q ,  x )

returns

 "JonL"

(no change

)

20.12.35

public String toLowerCase()

If this

String

 object does not contain any character that is mapped to a different

character by the method

Character.toLowerCase

 ( 20.5.20), then a reference

to this

String

 object is returned. Otherwise, this method creates a new

String

object that represents a character sequence identical in length to the character

sequence represented by this

String

 object, with every character equal to the

result of applying the method

Character.toLowerCase

 to the corresponding

character of this

String

 object.

Examples:

"French Fries".toLowerCase()

returns

 "french fries"

"

".toLowerCase()

returns

 "

"

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