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javamethod-parametersdouble-brace-initialize
user1382306
user1382306

Reputation:

method parameters in double brace initialization?

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?

Upvotes: 2

Views: 242

Answers (2)

morgano
morgano

Reputation: 17422

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.);
            }}
        )
    );
}

Upvotes: 1

Jeffrey
Jeffrey

Reputation: 44808

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"?

Upvotes: 3

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