Why are the methods of the Math class static ?
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Say, I have a reference to a Class object with SomeType having a static method. Is there a way to call that method w/o instantiating SomeType first? Preferably not escaping strong ... |
I got this question for homework, and all I can think of is to return a subclass of an abstract superclass.
Thanks!
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Lets assume that a rule (or rule of thumb, anyway), has been imposed in my coding environment that any method on a class that doesn't use, modify, or otherwise need any ... |
private static Importable getRightInstance(String s) throws Exception {
Class<? extends Importable> c = Class.forName(s).asSubclass(Importable.class);
Importable i = c.newInstance();
return i;
}
which i can also write
private static ...
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I'm going through the book Just Java 2 but am evidently missing something basic. These are two separate projects. I've generated a JAR for the second and added it ... |
I have a static Java method, where I want to know who is its caller. Is it possible to get this information in Java?
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I'm trying to write some Java code for a set of enum classes.
Each of the enums encapsulate some conceptually distinct data, so it doesn't make sense to combine them. The enums ... |
I have a method "b(Class g)" in a static class "a"
so
myclass.java contains...
public static class a{
public void b(Class g){
....
...
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Suppose I have a class with several static void methods, for example:
class MyClass {
public static void doJob() {
// ...
...
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Instructions: Write a static method createAdult for Person that returns a special instance of this class. The instance represents a generic adult and has the name "An adult" and the age ... |
Hi, In the following code snippet, class Base { public static void write(string data) { System.out.println(data); } } class Sub extends Base { public static void write(string data) { System.out.println(data); } } class SomeOther { public static void main(String args[]) { Base.write("Hello World"); } } Can the sub class's write method be called by calling Base class's write method. I know ... |
Hi, I have been making sense of the call to a static method through the Class containing the method Vs the object instance of the class. Apart from the obvious logical reason, I would like to know whether any difference lies in the manner the compiler look at this. I assume that compiler would resolve the call to the static method ... |
Friends, I have a question that I could not solve at the moment, since my codes are long and complicated, so I made a simple case, as the codes below: /** *Functions used by Servers */ public abstract class ServerFunction{ public static void printMyName(){ //here, i want to print the class name //who extends this abstact class //I could use the ... |
Hi, Is your question "How can I create an instance of "Hii" from code in main(String[]) ? The answer is, simply enough, that you can't. Classes local to a method can't be constructed in any code outside that method; whether there are parameters, or whether the methods are static, have no bearing on the question. |
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Hello, I have a question I can't find the answer for. Maybe here I can find it. In short the question is: can I invoke static methods of a certain class when I only have the Class object? The situation is this: 1. I have a class com.company.tool.SomeThing with method public static void methodA() and field public static final String SOME_FIELD. ... |
Not an Advanced question. It's about the basic language. Originally posted by Akhilesh Trivedi: 1. Is constructor for an abstract class really necessary? Assuming the abstract class is going to be subclassed by a concrete subclass, then the abstract class constructor is called when the concrete subclass is instantiated. The subclass cannot know how to initialise its superclass, so this makes ... |
class Example{ static A(){ // somthing } public static void main(String []args){ Example.A(); // line 1 } } this runs fine. tell me how can be a static method of the class Example is called by the name of class only. i.e. (Same in the case of Math class) Why there is no need to create explicit object of Example class? ... |
Hello, I have a class that doesn't have package name(default to .) with many static methods. I can't seem to import these without hitting compiler error. The only solution I have is to add a package declaration to the class. Is there a way to do it without it? I have the following: //file1 public class StaticThings { public static void ... |
I need to create a class that will hava a method to gather email addresses from a remote data source. I can accomplish this in WDSC for use in my web apps. However, I need this class so I can put it in a jar file that can be used from a remote call on our iSeries server. I have created ... |
Don't know. Don't understand the question. But as a general rule in object-oriented programming, instance fields and methods are the norm, and static members are used under special circumstances. A static member is shared throughout the class between all instances, and cannot take information from, nor pass information to, a particular instance. So static members tend to be in the minority. ... |
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You will be able to access them without instantiating the object (i.e. with the new keyword) If all the methods are static, you will not be able to use them to alter non-static information in an instantiated object if you DO instantiate the object. You will defeat the idea of object oriented programming because the objects you create will not have ... |
Regarding abstract static methods (as well as why interfaces can't have static methods), does not it all come down to method binding? Static methods, by design intent, are not to be associated with instances. So, I am betting the fathers of Java decided to go ahead and bind at compile time. As abstract methods have no known implementations at compile-time, there ... |
why am i able to call a static method using an object of that class ... when it can only be called using the classname.methodName() format // testing the keyword super // testing whether static methods can be overloaded and overridden // testing if a static method can be called using the object and not the classname // testing what happens ... |
I'm new to Java and I'm writing my first program (straight out of the textbook) that uses a class I just created in the same package. My program calls a static method from a simple class I just created. I get the following error message: TestRandomCharacter.java:11: cannot find symbol symbol : variable RandomCharacter location: class Chpt5.TestRandomCharacter char ch = RandomCharacter.getRandomLowerCaseLetter(); Here's ... |
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The class filereadingusingscanner.java is the entry point fo the application. It has a method to instantiate an object of type Student. It also requests for a File name. Later, sends this file name and Student object to a static method called toFile(Student stu, String filename), so that the Student deatils can be written into a file. But there appears to be ... |
Hey there, i've tried to write a class and a testclass to.. test it. it looks like this: Java Code: public class Raute{ static int i, j, hoehe; String zeichen; public static void Raute(int hoehe, String zeichen) { for (i = 0; i < (hoehe/2)+1; i++) { for (j = 0 ; j < hoehe; j++) { if ( (j > ... |
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hello, i am getting into a habit of making classes abstract and including lots of static methods that take another object as an arg and then performs some calculation or transformation of it, is this a bad idea, would it be better to not make the class abstract and make it have a private constructer instead? I have just realised that ... |
SidGate wrote: I said new Main().ToonScherm() ok sorry lil typo.. but with this I get a whole list or errors in the console.. =( Exception occurred during event dispatching: java.lang.NullPointerException at java.applet.Applet.getCodeBase(Applet.java:152) at Main.MaakURL(Main.java:1047) at Main.ToonScherm(Main.java:1258) at KeuzeScherm.actionPerformed(KeuzeScherm.java:212) at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995) at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318) at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387) at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242) at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236) at java.awt.Component.processMouseEvent(Component.java:6038) at javax.swing.JComponent.processMouseEvent(JComponent.java:3260) at java.awt.Component.processEvent(Component.java:5803) at java.awt.Container.processEvent(Container.java:2058) at java.awt.Component.dispatchEventImpl(Component.java:4410) at java.awt.Container.dispatchEventImpl(Container.java:2116) at ... |
Hi, I am new to Java Programming. I have written two class files Dummy1 and Dummy2.java in the same package Test. In Dummy1.java I have declared a static final variable and a static method as you can see it below. package Test; import java.io.*; public class Dummy1 { public static final int var1= 10; public static int varDisp(int var2) { return(var1+var2); ... |
the requirement asks me put the two classes in one package. this is the requirement" Write a class called Caesar, with static methods for enciphering and deciphering files with given keys. . The first line of the source code file should start with the package declaration, viz. package cipher ; In the same package, for use by the two methods, create ... |
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I have an abstract report class AbstractReportClass which I am extending in multiple report classes (one for each report, say ReportA, ReportB, ...). Each report class has its own static column definitions, title, etc., which I have to access through a static method getDataMeta() in a web application. Each report has the same exact code in getDataMeta, and no report may ... |
@jverd: I already set the classpath with my IDE, so I did it again the same way, and now it seems to be working. Thanks! @paul: I did not realize about the other List classes. The programs seems to be referencing the correct classes. And what I posted was just a tiny part of the program. There are many more class ... |
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Hello. I have an abstract class A where I have a static method blah(). I have 2 classes that extend class A called B and C. In both classes I override method blah(). I have an array with objects of type B and C. For every instance object of the array, I'm trying to call the static method in the corresponding ... |
I have a number of abstract classes that have all static methods, NO instance methods. The reason is I don't want people to instantiate these classes and all they need to do is to invoke static methods on them. I want all these classes to implement a certain number of static methods. So when someone create a new abstract class, they ... |