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Does Java have something like C#'s ref and out keywords?

Asked 2010-05-10T21:21:15.880
145

Something like the following:

ref example:

void changeString(ref String str) {
    str = "def";
}

void main() {
    String abc = "abc";
    changeString(ref abc);
    System.out.println(abc); //prints "def"
}

out example:

void changeString(out String str) {
    str = "def";
}

void main() {
    String abc;
    changeString(out abc);
    System.out.println(abc); //prints "def"
}
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1 Answer

34

Direct answer: No

But you can simulate reference with wrappers.

And do the following:

void changeString( _<String> str ) {
    str.s("def");
}

void testRef() {
     _<String> abc = new _<String>("abc");
     changeString( abc );
     out.println( abc ); // prints def
}

Out

void setString( _<String> ref ) {
    str.s( "def" );
}
void testOut(){
    _<String> abc = _<String>();
    setString( abc );
    out.println(abc); // prints def
}

And basically any other type such as:

_<Integer> one = new <Integer>(1);
addOneTo( one );

out.println( one ); // May print 2
answered 2010-05-10T21:38:32.803

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