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Java “The blank final field may not have been initialized” Anonymous Interface vs Lambda Expression

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余生分开走
余生分开走 2020-12-06 15:49

I\'ve recently been encountering the error message \"The blank final field obj may not have been initialized\".

Usually this is the case if you try to refer to a field t

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  • 没有蜡笔的小新
    没有蜡笔的小新 (楼主)
    2020-12-06 16:46

    I had a similar problem:

    import java.util.function.Supplier;

public class ObjectHolder {
    private final Object obj;
    public Supplier sup = () -> obj; // error

    public ObjectHolder(Object obj) {
        this.obj = obj;
    }
}



    And resolved it this way:
    


    public Supplier sup = () -> ((ObjectHolder)this).obj;



    Neither this.obj nor ObjectHolder.this.obj worked in Eclipse (though the latter worked for the standard JDK compiler).
    


    In your case, use this workaround, it is safe for all compilers:
    


    ((Foo)this).obj.toString();

    


    Another solution is to use a getter. In my example, it looks like this:
    


    public Supplier sup = () -> getObj();

private Object getObj() {
    return obj;
}

    
    
             
    
                                                        
    
            
            
    
              
                
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