Code Advice #14: Don't initialize fields to default values

(See intro for a background and caveats on these coding advice blog entries.) If you've been coding in C, you've probably picked up the habit of initializing all your fields: char *foo = NULL; int bar = 0; This is necessary, because in C, memory can be left uninitialized, so there's no telling what value foo will have before it is assigned something. In Java, however, the language specification clearly defines default values, so virtual machines will for example always initialize reference fields to null. Specifically, this means that code like the following is redundant: private int foo = 0; private Bar bar = null; private boolean baz = false; The alternative form of initializing the fields explicitly in the constructor, is the same: private int foo; private Bar bar; private boolean baz; public Foo() { foo = 0; Bar bar = null; baz = false; } You can leave out the above initializations, and the program will behave the same way. Carl Quinn once convinced me that this was more readable, so I picked up the habit, and I now swear by it. On the one hand, you can argue that leaving the explicit initializations in is more readable because you're making it really clear what it is you are intending. On the other hand, Java programmers quickly learn what th...

Date: October, 16 2006
Url: http://blogs.sun.com/tor/entry/code_advice_14_don_t

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