final

Can anyone tell me the use of making main method as final in java. while this is allowed in java public static final void main(String[] args) { } I dont see any use of making it final. anyways it is static so we can not override it. aioobe Adding final to a static method can actually make a difference. Consider the following code: class A { public static void main(String[] args) { System.out.println("A"); } } class B extends A { public static void main(String[] args) { System.out.println("B"); } } class C extends B { } public class Test { public static void main(String[] args) { C.main(args);

While checking the source code of Java's BigDecimal class, I was surprised that it was not declared as a final class : Class BigDecimal public class BigDecimal extends Number implements Comparable<BigDecimal> Immutable , arbitrary-precision signed decimal numbers. (from the Oracle Docs ) Is there a specific reason for this or did the developers just forget to add that keyword? Is it a good practice to not declare immutable classes as final? The same goes for BigInteger , but not for String which is declared as final. Quote from https://blogs.oracle.com/darcy/entry/compatibly_evolving

Why are people so emphatic about making every variable within a class "final"? I don't believe that there is any true benefit to adding final to private local variables, or really to use final for anything other than constants and passing variables into anonymous inner classes. I'm not looking to start any sort of flame war, I just honestly want to know why this is so important to some people. Am I missing something? Intent. Other people modifying your code won't change values they aren't supposed to change. Compiler optimizations can be made if the compiler knows a field's value will never

From page 113 of O'Reilly's Essential ActionScript 3.0 (2007): Methods that are final help hide a class’s internal details. Making a class or a method final prevents other programmers from extending the class or overriding the method for the purpose of examining the class’s internal structure. Such prevention is considered one of the ways to safeguard an application from being maliciously exploited . Does this refer to users of the API of a compiled, closed-source package, and "maliciously exploited" to learning things about the class design? Is this really a problem? For some more context, it

Consider this code snippet: public static void main(String[] args) { int z1 = 0; final int z2 = 0; System.out.println(false ? z1 : 'X'); System.out.println(false ? z2 : 'X'); } When running this code, I would expect to see two X in your console. However, the real output is: 88 X If we take a look at the Java specifications regarding the ternary operator , we found that If one of the operands is of type T where T is byte, short, or char, and the other operand is a constant expression of type int whose value is representable in type T, then the type of the conditional expression is T. So the

I have a final class Ring defined as: final class Ring { public static final int OUT = 3; public static final int MID = 2; public static final int IN = 1; } I also have a public class MorrisBoard with the following code: public class MorrisBoard { public static final Ring RING = new Ring(); private boolean checkMillBy(int ring, int x, int y) { switch(ring) { case MorrisBoard.RING.OUT: //... case MorrisBoard.RING.MID: //etc. //... } return false; } MorrisBoard.RING.OUT references a variable which is immutable for the lifetime of the program. All values are final. However, I still get the

I have a final non-static member: private final HashMap<String,String> myMap; I would like to initialize it using a method called by the constructor. Since myMap is final, my "helper" method is unable to initialize it directly. Of course I have options: I could implement the myMap initialization code directly in the constructor. MyConstructor (String someThingNecessary) { myMap = new HashMap<String,String>(); myMap.put("blah","blahblah"); // etc... // other initialization stuff unrelated to myMap } I could have my helper method build the HashMap, return it to the constructor, and have the