method parameters in double brace initialization?

Question

I'm creating a HashMap inline with double braces inside a function:

public void myFunction(String key, String value) {
    myOtherFunction(
        new JSONSerializer().serialize(
            new HashMap<String , String>() {{
                put("key", key);
                put("value", value.);
            }}
        )
    );
}

and I'm receiving these errors:

myClass.java:173: error: local variable key is accessed from within inner class; needs to be declared final
                        put("key", key);
                                   ^
myClass.java:174: error: local variable value is accessed from within inner class; needs to be declared final
                        put("value", value);
                                     ^
2 errors

How can method parameters be inserted into an Object double brace initialized?

@Smit i don´t think so: he is just calling a function for which he inline creates obejcts and calls member functions of them. — luk2302, Jul 24 '13 at 23:37
If you use an IDE, it would be able to auto-correct this error for you. — Peter Lawrey, Jul 24 '13 at 23:49
If your Map really contains just one key and one value, you could also do `new JSONSerializer().serialize(Collections.singletonMap(key, value))`. — VGR, Jul 24 '13 at 23:56
[Every time someone uses double-brace initialisation, a kitten gets killed](http://stackoverflow.com/a/27521360/521799) — Lukas Eder, Dec 17 '14 at 08:52

score 3 · Accepted Answer · edited May 23 '17 at 12:03

3

Declare your parameters as final:

public void myFunction(final String key, final String value)

Also, you might want to take a look at Efficiency of Java "Double Brace Initialization"?

edited May 23 '17 at 12:03

Community

1
1

answered Jul 24 '13 at 23:36

Jeffrey

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bingo. genius. i tried it inside the initialization which gave even more errors. didn't think to do it to the parameters. thx! – Jul 24 '13 at 23:38

score 1 · Answer 2 · answered Jul 24 '13 at 23:36

Compiler will complain if you use non final local variables in inner classes, fix it with this:

public void myFunction(final String key, final String value) {
    myOtherFunction(
        new JSONSerializer().serialize(
            new HashMap<String , String>() {{
               put("key", key);
               put ("value", value.);
            }}
        )
    );
}

method parameters in double brace initialization?

2 Answers2