This question already has answers here:
Why doesn't Java allow enum to be defined within a method? [duplicate]
(3 answers)
Closed 8 years ago.
Java does not allow enum to be declared in a method that is a basic java syntax.
But
Could any body explain why is that, what could have gone wrong if it would have been allowed by Java, I am sure there must be some cause behind this restriction, any idea?
class Example {
void aMethod() {
//This is not allowed
enum Status {
NEW,
PROCESSING,
COMPLETED;
}
}
}
enum types are typically used to share constant values between classes so declaring them in the scope of a method wouldnt make any sense
Related
This question already has answers here:
Why should I use the keyword "final" on a method parameter in Java?
(12 answers)
Closed 1 year ago.
I have a look at several questions e.g. In Java, should I use “final” for parameters and locals even when I don't have to? on SO and I am a little bit confused after reading the suggestions and answers.
In the project that I ma working on, there are lots of final keywords for the method parameters in methods and interfaced as shown below:
interface:
MenuDTO findMenu(final UUID menuUuid);
implementation:
#Override
public MenuDTO findMenu(final UUID menuUuid) {
}
As far as I know, using final keyword for method parameters as shown above is pointless. So, should I remove the final keywords from the interface methods and their implementations?
I also see no meaning in using final in parameters in Java. The final means you cant cant reassign value to variable. This you cant reassign anyway since the value is parameter. It looks for me like this style of writing final is coming from someone who worked with C++ before Java.
This question already has answers here:
Does the order of declaration matter in Java/C#?
(12 answers)
Closed 4 years ago.
I know that some programming languages require methods that are referenced/called by other methods to be declared before the caller in the code. For example:
private Method1(in){
Return in *5;
}
Private Method2(paycheck){
Return Method1(paycheck);
}
would be OK but,
Private Method1(paycheck){
Return Method2(paycheck);
}
Private Method2 (in){
Return in *5;
}
Would fail.
Is Java, and/or Android specific Java, one of these languages?
No, in Java and other Android languages (Kotlin, Dart) doesn't do compiling like C, it's okay to write methods or even variables anywhere inside the class.
This question already has answers here:
What is Implicit constructors on Java
(2 answers)
Closed 7 years ago.
In what situation we implement the explicit constructors in java program and when we doesn't need to implement explicit constructors.
This article explains the full story. In short: you need explicit constructors if you want to pass parameters to this constructor. If you do not need this, you can either provide a "parameterless" constructor ( public Foo() {} ), or you do nothing, in which case the system will create an empty one for you in the background.
This question already has answers here:
What is the use of marker interfaces in Java?
(10 answers)
Closed 8 years ago.
I am confused about marker interfaces in java.
Could anyone please tell me when we have no methods in marker interfaces, then from where it is called. Do we have to implement this explicitly also.
It's just like any other interface.
And used to type check the object at run time.
For ex:
And somewhere else Runtime realizes objects like
if (SomeObjImpMarkerInterface instanceof SomeMarkerInterface ) {
// Hey this object is that type
} else {
// Not that type.
}
This question already has answers here:
Closed 11 years ago.
Possible Duplicate:
Protected methods in objective-c
I am a Java developer who is starting to have questions about Objective-C coding syntax.
As of right now, I only see +/- that denotes the Java public/private equivalents.
How would you implement a protected method in Objective-C?
+/- indicates whether a method is a class method or an instance method -- not whether it is public or private.
In short, you can't declare a method as protected in Objective-C. Essentially every method is public, although if you don't declare a method in the header file, it is, in effect, private.