I can't seem to access instance members of the surrounding class from inside an enum, as I could from inside an inner class. Does that mean enums are static? Is there ... |
I want to make some data easily available throughout my application. I have a few variables in a class with static data, which get written to and read from at several ... |
What do you think of the following way to simulate a static class in java?
You can add non static methods but you wouldn't be able to call them.
/**
* ...
|
I've read elsewhere that a static anonymous class doesn't make sense - that all anonymous classes should be tied to an instance of the enclosing type. But the compiler let's ... |
I want to write a static class customer ID that begins with C1000, and for each new customer object created it will add +1, C1001, C1002, C1003, and so on. ... |
why a class can't be declared as static ..?
|
How do I declare a static class in java? eclipse wants me to remove "static" from the declaration.
static public class Constants {
|
|
I have a program that handles different objects which have their own sort of instructions set (say their own program), and from a main class I want to run these programs. ... |
say I have jcifs-1.3.14.jar in my lib folder, and I have a class that is importing from the library and uses the classes like:
import jcifs.smb.*;
NtlmPasswordAuthentication auth = new NtlmPasswordAuthentication(domain,
...
|
class Coffee{
enum CoffeeSize{BIG,HUGE,OVERWHELMING}
CoffeeSize size;
}
class CoffeeTest{
public ...
|
I have read that I can define a class as static, but I don't understand why I might need to do so. What good are static classes? When might I need ... |
I know that internal class has to be static because will link between public and internal classes and internal class will be created all times that created public classes.
And my question ... |
For example: I have to use the date class in my project, but i need for example easy methods to add minutes to a Date etc. Should I:
Make a static class ... |
even though i got lot many answers when i googled it. I really could't find a satisfactory answer..
so someone please help me out..
Thanks in advance
|
Is there anything like Static Class in java?
What is the meaning of such a class. Do all the methods of the static class need to be static too?
Is it required the ... |
I am new to Java, and was reading synchronized blocks stuff. I got confused in one of the statement, that during the static class the synchronization uses class instance and normal ... |
Possible Duplicate:
Static nested class in Java, why?
I know about the static fields in java. But don't know why we create a static class. Any ... |
I have made the static class below so any class may access any of my lejos robot's sensor methods without me having to make an instance for each class.
However whenever ... |
As static classes are not tied to any instance, is the following a good example (from a philosophical POV) of using a static class:
A spare tire (for a road vehicle), as ... |
Could someone please explain why are attributes of a class are not ordinarily defined to be static.
|
I am experimenting here a bit.
Say I have a class :
static class MyClass {
static String property = "myProperty";
}
and a method:
public static void myMethod0(Class<MyClass> clazz) ...
|
Following is the simplest example of static inner class in Java. Let's look at it.
package staticclass;
final class Outer
{
final public static class Inner
{
...
|
I'm getting IllegalAccessException, however JNI calls such methods without problem, here in the case: class Hello { public static void main(String...args) { System.out.println("Zdorovo"); } } You can execute such class from java, however if I try to use reflection, I get the exception above. Is any way to avoid this without JNI? Note: I have no access to source code of ... |
The only class you can declare static is a member class... And this member class can be instantiated only in the context of the class which the member belongs to. If you want to avoid this , you can declare the member class as static and you can use this class the same way as you do the top level (to ... |
|
The top level class never be static. IT is language defined. Class is intended to create objects to make useful. Static things not belong to any object. They have defined like that. But static inner classes exists, means that that class object can be accessed with out having the object of the top level class. |
Hi, in the class below without declaring the class one as static if we are going to declare class two as static it is giving a compile error . why is it so i can't get the exact reason for this pls. explain. public class outer { static class one { static class two { public void main() { System.out.println("two"); } ... |
|
A friendly place for programming greenhorns! Register / Login Java Forums Java Java in General Problem With 'static' When Running Stand Alone Java Class Post by: JiaPei Jen, Ranch Hand on Nov 08, 2006 16:05:00 I have a Java class that recursively builds a 'tree' . This Java class works as I expected without problem. I am able to ... |
|
I think you should look into the Singleton pattern. That allows you to have only one instance of a class; similar to having only one "instance" of a static variable within a class. This is, as I understand it, what you are looking for. [ May 29, 2007: Message edited by: Andris Jekabsons ] |
Yes and No. There are a number of different types of class in Java, these can be grouped in to 2 main categories Top Level Classes and Inner Classes. Inner Classes can be subdivided into 4 types Anonymous, Local, Member and Nested Top Level. Of all these class types only one type can use the static keyword, that is the Nested ... |
The only kind of "static class" is a nested class marked "static", and in fact these are extremely similar to normal top-level classes. A nested class that's not marked static is associated with one specific instance of the containing class; a static nested class is not. That's the only difference. As far as classloaders go: a JVM almost always has more ... |
|
If I have a static class do I have to declare the methods static within it? Below you will find some sample code that is a private inner class that acts as a helper for a DataBase Conection Pooling class. Our confusion comes from whether or not this will behave properly. It compiles and runs but we have issues with to ... |
Why does the 'greeting' method from 'XSuper' get executed and the 'name' method from 'XSub'. I thought they should be from 'XSub', and the result should be "Hello, Dick". however, it is actually "Goodnight, Dick". class XSuper { static String greeting() { return "Goodnight"; } String name() { return "Richard"; } } class YSub extends XSuper { static String greeting() { ... |
Hi I used a static method that I made to invoked a non-static method that the java team made. In the compiling time I receive a compiler error: "ClientProfile.java": Error #: 308 : non-static method remove(java.awt.Component) cannot be referenced from a static context at line 76, column 5 I understand that the invoked remove() has to be static or move the ... |
The soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - ... |
|
|
If I have an object in a program that shouldn't be duplicated, (it should only be created once), should the class that defines that object be "static"? As an example: I have defined a LapCounter class to count the number of times a RaceCar object makes a lap around the track. I only need one LapCounter object. Should I simply define ... |
My question is referring to this following code, based on a very simple card game. I was wondering if it is more common to access and instatiate members of an object referring to a type class card by directly referencing the reference variable p1 & p2, like I have done in onecard.java? (referenceVariableName.memberName) My instructor is insisting that we include the ... |
Originally posted by Amit Saini: Hi, Think of "static" keyword as "one per class". That's misleading and not helpful, because the keyword static is actually working overtime, when it is allowed to modify member classes: class T { class B { void b() { System.out.println(t); } } static class C { void c() { //System.out.println(t); //^^non-static variable t cannot be referenced ... |
Ranchers: Consider this: class One { private static double d1; static class InnerOne { double mothod() {return d1;} } } This code can successfully be compiled. Two questions from me are: 1. What would be the scenarios that we need to put an inner class into a class? What is the meaning actually having a class in a class? (I mean ... |
Hello together, I have a question about static. In most places it says, a static variable or method only exists in the class, there it is declared. Really? Hm, the following does not agree with this: package abcde; public class Bird { protected static int referenceCount = 0; public Bird() { referenceCount ++; } protected void fly() {} static int getRefCount() ... |
Hi, Please can someone explain me this basic concept.I have read about it before but can't recollect now. Why does line 3 gives compilation error if I don't write static in front of ReSortComparator class? Also can someone why we make a class static(advantages)? Thanks in advance import java.util.*; class SearchObjArray { public static void main(String [] args) { String [] ... |
What error? Please supply fuller details. Are you trying to declare a top-level class as "static?" "Static means it belongs to the class it is in, not to any instance of that class. If it isn't "in" a class, how can it "belong to" that class and how can it be "static?" |
What's a property in a class? Not standard Java nomenclature. You mean a field. You get access to a private static field the same way you get access to a private instance field-with an accessor (get) method. If the class has a private static field without a public [static] get method, then whoever wrote that class doesn't intend to grant you ... |
|
Hi Guys I have a static utilities class which holds common methods. I have several static methods which convert strings to longs, and vice versa and returns the value to the requesting method. My question is will this cause a problems if multiple users are making the same request at the same time ? See a snippet of code below: // ... |
That is not a class you are declaring static, but a reference to a Scanner object. Yes, you can have static references, as you have already seen. System.in is not a method because it hasn't got enough (). It is a static member of the System class, which is a reference to a Stream which takes input from the keyboard at ... |
|
Hi Tristan, static methods or variables are (usually) not a good idea. They have some disadvantages and you lose advanced object oriented core features like inheritance or polymorphism. Moreover modern JVMs and garbage collectors are even optimized for object creation and collection (as far as I know). So concepts like object pooling to save memory or gain performance are not necessary ... |
Top-level classes You declare a top-level class at the top level as a member of a package. Each top-level class corresponds to its own java file sporting the same name as the class name. A top-level class is by definition already top-level, so there is no point in declaring it static; it is an error to do so. The compiler will ... |
|
|
|
|
Hi, I am a fairly experienced C# coder, but new to Java. My question is a general programming question: - Usually a class which has no internal state (ie fields) is a good candidate for being made static (So doesn't change its reciever class). However, is there ever a reason to make a class holding internal state (fields) a static class? ... |
Top-level classes cannot be declared static. It's not useful to be able to declare top-level classes static; what it means to do that is not defined in the Java language specification. So, why would you want to be able to declare a top-level class static, if it doesn't mean anything? The extra word static would only confuse people. So it's a ... |
Hi , Please let me know the advantage of defining the class as static.Because while discussing about the perofrmance issue in our project,the manager has recommended to make the classes static whereever it is possible. Is it really helps to improve performance? And at which context we have to make the class static? |
|
Always; unless the class needs access to non-static members of its enclosing class. Think of a non-static inner class as one that has an extra field which has a reference to an instance of the outer class. So you can see, if it doesn't use methods or fields of the outer class, it's just a waste of space, so make it ... |
Neatness mainly. And logical grouping. If the enum is small and associated purely with what is going on in the outer class then maybe keep it in there, but if it's for use outside the class, and/or has a load of its own code then I'd consider sticking it in its own file. Unless (as said above) you need access to ... |
|
|
|
|
|
when we are declaring an inner class with static key word what does it meant.why cant we use static modifier in case of normal class.what is the advantage we r getting in terms of performance when we r declaring an Inner class as static.I know in case of static variable,That belong to Class,All instances share the same copy,And in case of ... |
|
mlk wrote: enums could not be inner classes No, enums are not normal classes, and compared to "inner classes" is it what thy call static nested classes that is most close. But it is still in a way a class, one that not may be explicitly instantiated and sub classed, but one that may have its own static and/or instance methods. ... |
|
Hi All, I have gone through en number of web-sites but i don't get a clear definition and a clear cut picture about static class in java I had plenty of questions in my mind. Somebody here - Java gurus and experts kindly please help me to understand about these things. What is static class ? When to declare a class ... |
I'm not 100% sure why it is giving you that error message, but I believe it is because it appears that you're trying to make a static variable (because you're using it as if it was a static variable (just think of it like a global variable if you don't understand static)). |
Hi Folks, Just curious about something that I have come across and I was hoping that people here could confirm my assumption or possibly clarify somethings for me. I came across a class that has code enclosed within brackets and the static keyword that is outside of the body of any methods and is just at the class level. So it ... |
|
Hi all, got a problem I can't seem to find a solution for, so hoping someone knows what to do with this! I'm running a Java applet in a browser, under Sun's JVM. It has a custom dynamic class loader, which queries our server and downloads patches to the software. However, this doesn't work entirely as planned. The JVM doesn't seem ... |
Hi All, I have a class filled with static helper methods that I use to render text documents. I would like to start rendering these documents in another format and thus extend my helper class and override the format dependent methods. Is there a way that I can choose which version of this class to use without instantiating it. I ask ... |
I have a static class which stores some system messages, normally i'll call it by using: if(success) System.out.println(MyMessage.message01); else System.out.println(MyMessage.message02); now my system want to support two languages, english and japanese what should i do by not touching the calling method (like the example above), and do checking at the MyMessage static class? if it wasnt a static class i think ... |
Hello at the start of my programme I would like to store some valuse (the values are trhe user rights that will be read from the data base) these values will never change during the execution of the programme. so I was told that the best is to create a static class ... can any one post an example of static ... |
|
|
while i am aware of that potential problem i am not so sure how it applies to my current problem. if i simply create a scanner object (called scan with a lowercase s) and use the following code, as i did in the previous (working) version of my program System.out.print ("Enter the coefficient of x^4 (0.0 if none): "); coeff4 = ... |
|
according to my understanding static makes the same copy to all objects... No. static components are attached to a Class object, whereas instance components are attached to an instance of the class. No copying is involved. You don't even require that an instance of the class exists in order to access static fields or members. It's the same with nested classes. ... |
|
|