再说final变量（Again, the final variable）.docVIP

再说final变量（Again, the final variable） Again, the final variable From jdk1.0 to today, JAVA technology has undergone great changes in technology over the past ten years, but the definition of the final variable comes from it No changes have taken place since the day of birth, that is, for more than 10 years, it has always indicated its original meaning But unfortunately, after more than 10 years, 90% still dont understand its true meaning, and there is no article, including all the introductions I have seen JAVAs books (including TKJ) are not clear, and Im sure some authors understand it, but none of the authors make clear to the reader Most people were run over by a nonsense final, finalized, finally article on Java (blushing: me too) The definition of a final variable is not complex in itself, that is, once a variable is initialized, it cannot point to any other object. In c++, it is a const pointer, whereas it is a pointer to the object Not a pointer to the const variable. The const pointer means that it can only point to the address at the time of initialization, but the object itself in that address Can be modified. The pointer to the const variable means that the object itself cannot be modified Such as: final, StringBuffer, sb = new, StringBuffer (Axman); Sb = new StringBuffer (Sager); / / error, Sb no longer point to other objects. Sb.append (was changed); the ground image that the //sb points to itself can be modified Start with the final variable initialization: A lot of articles say so: it can be initialized in two places, one is its definition, and the two is in the constructor, and the two can only choose one. Nonsense! The final variable can be initialized at any point where it can be initialized, but can only be initialized once. Once initialized, it cannot be assigned again Values (re - pointing to other objects) must be explicitly initialized as member variables, and temporary variables can only be defined without initialization (and certainly not ref