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.
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:
Unable to #Override the compareTo() method in Java
(5 answers)
Closed 4 years ago.
I have simple class with 2 fields. I want to be able to sort objects of this class so I implement a compareTo() method. The field I want to use for sorting is an int. So my method is pretty simple ..
public int compareTo(macToPortMapping pnum) {
// we want to be able to sort a mapping based upon the port number
return this.portNo - pnum.portNo;
}
This seems consistent with everything I've read about implementing a comparable. Still the netbeans wants to remove #Override and my compile message "method does not override a method from a supertype"..
This doesn't mean anything to me. Any pointers?
Well, I found a solution --
in my class declaration I had to include an implements..
public class macToPortMapping implements Comparable<macToPortMapping>{
int portNo;
macAddress addr;
}
when I put that on the class, it all worked as expected. I don't know how I missed that in the reading.
This question already has answers here:
Global variables in Java
(25 answers)
Closed 6 years ago.
I need to have certain info inside my program which I need to access and modify in between different classes inside different packages. I've tried using a separate class for them but it doesn't work because I need to make a new instance every time I use it in a different class.
Is there a way to solve this problem?
public class ClassName {
public static String varName = "this can be used globally;"
}
Now can be referenced globally by
ClassName.varName
Note: public is important since a private will not be accessible from the outside 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:
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