Getting class in a static method

I have a class with a static method. How can I return the class object with this method?
public class Pencil {
public static Class getClass() {
Class class = ??? (this.getClass(), can�t use!)
return class;
Thanks!

it would have to be like this:
public static Class getClazz() {
return Pencil.class;
}

Similar Messages

How to determine the Class of a static methods class?

hi,
is there a way to get the code below to output
foo() called on One.class
foo() called on Two.classthanks,
asjf
public class Two extends One {
   public static void main(String [] arg) {
      One.foo(); // should say "foo() called on One.class"
      Two.foo(); // should say "foo() called on Two.class"
class One {
   public static final void foo() {
      System.out.println("foo() called on "/*+something.getClass()*/);
}

- One.class won't resolve to Two.class when the static
method is called via the class TwoThat's because static methods are not polymorphic. They cannot be overridden. For example try this:
public class Two extends One {
   public static void main(String [] arg) {
      One.foo(); // should say "foo() called on One.class"
      Two.foo(); // should say "foo() called on Two.class"
      One one = new Two();
      one.foo();
      ((Two) one).foo();
   public static void foo() {
      System.out.println("foo() called on Two");
class One {
   public static void foo() {
      System.out.println("foo() called on One");
}

How to get the current class name in static method?

Hi,
I'd like to get the current class name in a static method. This class is intended to be extended. So I would expect that the subclass need not to override this method and at the runtime, the method can get the subclass name.
getClass() doesn't work, because it is not a static method.
I would suggest Java to make getClass() static. It makes sense.
But in the mean time, does anybody give an idea to work around it?
Thank you,
Bill

Why not create an instance in a static method and use getClass() of the instance?
public class Test {
public static Class getClassName() {
return new Test().getClass();

Force Derived Class to Implement Static Method C#

So the situation is like, I have few classes, all of which have a standard CRUD methods but static. I want to create a base class which will be inherited so that it can force to implement this CRUD methods. But the problem is, the CRUD methods are static. So
I'm unable to create virtual methods with static (for obvious reasons). Is there anyway I can implement this without compromising on static.
Also, the signature of these CRUD methods are similar.
E.g. ClassA will have CRUD methods with these type of Signatures
public static List<ClassA> Get()
public static ClassA Get(int ID)
public static bool Insert(ClassA objA)
public static bool Update(int ID)
public static bool Delete(int ID)
ClassB will have CRUD signatures like
public static List<ClassB> Get()
public static ClassB Get(int ID)
public static bool Insert(ClassB objB)
public static bool Update(int ID)
public static bool Delete(int ID)
So I want to create a base class with exact similar signature, so that inherited derived methods will implement their own version.
For E.g. BaseClass will have CRUD methods like
public virtual static List<BaseClass> Get()
public virtual static BaseClassGet(int ID)
public virtual static bool Insert(BaseClass objBase)
public virtual static bool Update(int ID)
public virtual static bool Delete(int ID)
But the problem is I can't use virtual and static due to it's ovbious logic which will fail and have no meaning.
So is there any way out?
Also, I have few common variables (constants) which I want to declare in that base class so that I don't need to declare them on each derived class. That's why i can't go with interface also.
Anything that can be done with Abstract class?

Hi,
With static methods, this is absolutely useless.
Instead, you could use the "Singleton" pattern which restrict a class to have only one instance at a time.
To implement a class which has the singleton pattern principle, you make a sealed class with a private constructor, and the main instance which is to be accessed is a readonly static member.
For example :
sealed class Singleton
//Some methods
void Method1() { }
int Method2() { return 5; }
//The private constructor
private Singleton() { }
//And, most importantly, the only instance to be accessed
private static readonly _instance = new Singleton();
//The corresponding property for public access
public static Instance { get { return _instance; } }
And then you can access it this way :
Singleton.Instance.Method1();
Now, to have a "mold" for this, you could make an interface with the methods you want, and then implement it in a singleton class :
interface ICRUD<BaseClass>
List<BaseClass> GetList();
BaseClass Get(int ID);
bool Insert(BaseClass objB);
bool Update(int ID);
bool Delete(int ID);
And then an example of singleton class :
sealed class CRUDClassA : ICRUD<ClassA>
public List<ClassA> GetList()
//Make your own impl.
throw new NotImplementedException();
public ClassA Get(int ID)
//Make your own impl.
throw new NotImplementedException();
public bool Insert(ClassA objA)
//Make your own impl.
throw new NotImplementedException();
public bool Update(int ID)
//Make your own impl.
throw new NotImplementedException();
public bool Delete(int ID)
//Make your own impl.
throw new NotImplementedException();
private CRUDClassA() { }
private static readonly _instance = new CRUDClassA();
public static Instance { get { return _instance; } }
That should solve your problem, I think...
Philippe

Completely stuck, get/set, Contructors and Static Methods

Hi any help would be very appreciated on this one,
import java.util.Scanner;
import java.io.*;*
*import java.util.*;
public class Course extends Program {
 public Course(String Coursecode, String Coursename){
 Coursecode = stuinput.courseCode;
public void getCoursecode(){
 return stuinput.courseCode;
//public String getCourseCode(){
// return this.courseCode;
 public static void printCourses() throws Exception
 stuinput[] courseObjArray = new stuinput[18]; //Make sure this is the same as the ammount in the text
 Scanner sc = new Scanner(new File("courses.txt"));
 int i=0;
 boolean found = false;
 while(sc.hasNextLine())
 //Delimit this line with scanner
 Scanner sc1 = new Scanner(sc.nextLine());
 sc1.useDelimiter(":");
 courseObjArray[i] = new stuinput(sc1.next(),sc1.next());
 i++;
 }//while
 for(int i1 = 0;i1 < courseObjArray.length;i1++)
 System.out.println(courseObjArray[i1].courseCode);
 System.out.println(courseObjArray[i1].courseName);
 System.out.println("-----------------");
 //This print the indexOf what you want to search
 class stuinput
 String courseCode = null;
 String courseName = null;
 stuinput()
 stuinput(String courseCode,String courseName)
 this.courseCode = courseCode;
 this.courseName = courseName;
import java.io.*;
public class gradCheck {
 public static void main (String args[]) throws Exception {
 Course.printCourses(); //Prints All Course but dont need that
}This ^^^ Is basically the driver class, Im trying to run the printCourse() from the 1st Class I posted.....but it's giving me lots of errors with everything I try, I'm trying to get the values out of that text file and have them broken up so I can use them amoung various class's, I want to use those values inside the Course class, as well as the Program Class and other Class's that extend off of that,
Any Ideas (im sure there are because im very new), as to how I might to that
Thanks :-) would be much appreciated

yes, I still have a lot to learn here I think, Thank you so much, that worked for me, I think I need to read a lot about all of this and understand it......thank you
If I may, one more thing which I'm really stuck on and if I can get this right, I think my whole program and ideas will just fall into place...Ive been trying to a couple of weeks now and can't quit get it right
in the above code,
this bit,
 class stuinput
 String courseCode = null;
 String courseName = null;
 stuinput()
 stuinput(String courseCode,String courseName)
 this.courseCode = courseCode;
 this.courseName = courseName;
 }how do I pass this off to another class through the constructor
public class Course extends Program {
 public Course(){
 }at the top....say If I want it to be used in the Program class.......or a student class that extends of the this current class above (Course Class)
Thanks,

Abstract class and a static method

Can i call a static method within an abstract class ?

public class AbstractDemo {
public static void main(String[] args) {
    BiPlane biPlane = new BiPlane();
    System.out.println("biplane propulsion = " + biPlane.getPropulsionType());
    JumboJet jumboJet = new JumboJet();
    System.out.println("jet load = " + jumboJet.confirmMaxLoad());
    System.out.println("jet speed = " + jumboJet.getTopSpeed());
    System.out.println(Airplane.confirmMaxLoad());
abstract class Airplane {
static String confirmMaxLoad() {
    return "go_get_um, yeehaa!";
public abstract String getPropulsionType();
abstract String getTopSpeed();
class BiPlane extends Airplane {
public BiPlane() {
    System.out.println("BiPlane constructor");
static String confirmMaxLoad() {
    return "400 lbs";
public String getPropulsionType() {
    return "propeller";
final String getTopSpeed() {
    return "130 knots";
class JumboJet extends Airplane {
public JumboJet() {
    System.out.println("JumboJet constructor");
public String getPropulsionType() {
    return "jet";
public String getTopSpeed() {
    return "mach .87";
}

Static methods in data access classes

Are we getting any advantage by keeping functions of DAOs (to be accessed by Session Beans) static ?

I prefer to have a class of static methods that
require a Connection to do their work. Usually, there
is a SessionBean that 'wraps' this DAO. The method
signatures for the SSB are the same, minus the need
for a Connection, which the SSB gets before delegating
to the Static Class.Uggh, passing around a connection. I've had to refactor a bunch of code that used this pattern. We had classes in our system that took a class in their constructor simply because one of their methods created an object that needed the connection. Bad news--maintenance nightmare--highly inflexible.
What we've done is create ConnectionFactory singletons that are used throughtout the application in order to get connections to the database. All connection factory implementations implement the same interface so they can be plugged in from other components at runtime.
In my opinion, classes that use connections should manage them themselves to ensure proper cleanup and consistent state. By using a factory implementation, we simply provide the DAO classes the means by which they can retrieve connections to the database and even the name of the database that needs to be used that is pluggable. The DAO classes do their own connection management.
For similar reasons, I eschew the static method concept. By using class methods, you make it difficult to plug in a new implementation at runtime. I much prefer the singleton pattern with an instance that implements a common interface instead of a class full of static methods.
I recently needed to dynamically plug in new connection factory implementation so that we could use JNDI and DataSources within the context of the application server (pooled connections) but use direct connections via the Driver manager for unit testing (so the application server didn't need to be running). Because of the way this was coded, I simply changed the original factory to be an abstract factory and changed the getInstance() method to return a different implementation based on the environment (unit test vs live). This was painless and didn't require changing a single line of client code.
If I had to do this using the previous code that I refactored, I would have had to change about 200 jsp pages and dozens of classes that were making calls to the static method of the previous factory or hacked in something ugly and hard to maintain.
YMMV

What is the purpose of Static methods inside a class?

Hi,
What is the purpose of Static methods inside a class?
I want the answers apart from "A static method does not require instance of class(to access) and it can directly be accessed by the class name itself"
My question is what is the exact purpose of a static method ?
Unlike attributes, a separate copy of instance attributes will be created for each instance of a class where as only one copy of static attributes will be created for all instances.
Will a separate copy of instance method be created for each instance of a class and only one copy of static methods be create?
Points will be rewarded for all helpful answers.

Hi Sharma,
Static methods is used to access statics attributes of a class. We use static attributes when we want to share the same attribute with all instances of a class, in this case if you chage this attribute through the instance A this change will change will be reflected in instance B, C........etc.
I think that your question is correct -> a separate copy of instance method will be created for each instance of a class and only one copy of static methods be create ?
"A static method does not require instance of class(to access) and it can directly be accessed by the class name itself"
Static Method: call method class=>method.
Instance Method: call method instance->method.
Take a look at this wiki pages.
[https://wiki.sdn.sap.com/wiki/x/o5k]
[https://wiki.sdn.sap.com/wiki/x/ZtM]
Best regards.
Marcelo Ramos

Static methods. Why?

I understand what static means, and that each class has only ONE copy of its static variables and methods.
I an see the benefits of using static variables, but i cant seem to get my head round the benefits of using static methods.
What is the advantage of this, and is there a common situation where they are appropriate? (not main)
Cheers

I don't think static exists to prevent namespace conflicts. I think that the reason for static to exist is just as I described it: When you've got some task that is appropriate to be performed by a specific class, but that doesn't make sense to be associated with a particular instance of that class.
For example, String.valueOf. It's appropriate for the String class to have a method that returns the String representation of anything you feed to it (so it's in the String class) but it doesn't make sense for that method to be associated with a particular instance of String (so it's static). After all, you don't yet have a String to operate on--you're producing the String.
Which raises another interesting point: I wonder what the design decision was that led to
String.valueOf(int)
String.valueOf(long)
String.valueOf(Object)
etc.
instead of
new String(int)
new String(long)
newString(Object)
etc.
I've used both patterns in my own work, but I don't really have any good criteria for picking one over the other.
One thing that comes to mind for the general case is that with the static method, you can return a subclass, which you can't do with a constructor. Conversely, with a constructor, the caller knows exactly which class he'll get, whereas with a static method he doesn't. Of course, these points don't apply to String, as it's final.
I'm new to java, but as far as I can tell, "static"
means "global". The reason for having them in classes
is mainly to prevent name conflicts. For instance,
you could have an Array object, and a List object, and
both could have sort() methods, but they may be very
different types of methods. By forcing sort() to be a
member of a class, instead of a global identifier, you
have Array.sort() and List.sort(), which is much
safer.
It seems that the java designers went to great lengths
to make sure there are no namespace conflicts in the
language. Maybe they even went a bit too far in this
sometimes.

Static Vs Non-static methods

Hello,
I wonder what should I use. I have got a class which does a lot of counting.. I can put the methods inside the class or make a class Math3D with the static methods that will count it.
Which is the better way?

BigDaddyLoveHandles wrote:
deepak_1your.com wrote:
Sorry mate... did not get that.By definition a utility class has all static methods. So as soon as you mention "utility class" you've already made a decision. The real question is "should method X be static or non-static"? My default position is to assume no method should be static, and then wait to be convinced.
Look at utility class java.lang.Math, for example. It has static methods sin(), cos(), sqrt(), etc... An obvious choice for a utility class, right? Then they introduced class StrictMath in 1.3 with exactly the same static method signatures. That's a code smell that one should have written an interface and implemented it in at least two ways, but it's too late for that because the original methods are static.Good post.

Need some explanations regarding static Method

Hello,
I have a code where a class has a static method access by other classes. This not working as I thought and I would like to understand why.
Here below is the code.
Here is a class having the static method "test"
package test;
public class StaticTest {
 public StaticTest() {
 public static void test (int i){
 while (i < 1000){
 System.out.println("i = " + i );
 i++;
}Here is the code of another class (Thread) using this static method. This Thread can be initialized with an integrer value that will be passed to the static Method.
package test;
public class ThreadTester extends Thread {
 int x;
 public ThreadTester(int i) {
 x=i;
 public void run(){
 StaticTest.test(x);
}Here is the code starting 2 Thread running in parallel and both are then calling the static method.
//start 2 thread accessing the static method.
 ThreadTester test1 = new ThreadTester(0);
 ThreadTester test2 = new ThreadTester(200);
 test1.start();
 test2.start();
...As the second thread is started with a bigger value I thought that we would only have seen few printouts from the first thread starting by 0 and then printouts starting by 200.
Here is what I thought regarding the result:
i = 0
i = 1
i = 2
i = 3
i = 200 --> startup of the second thread, x in static method is overriden (at least this is what I thought!)
i = 201
i = 202
i = 203
i = 204
i = 205
i = 206
i = 207
i = 208
i = 209
But the real result is:
i = 0
i = 1
i = 2
i = 3
i = 4
i = 5
i = 200
i = 6
i = 201
i = 202
i = 203
i = 204
i = 205
i = 206
i = 7
i = 207
i = 208
i = 209
i = 8
It seems that there is 2 instances running in parallel. I thought that it would'nt be the case with the word "Static".
Also I don't understand the result because if I use JBuilder in Optimizer mode I can see that there is only one instance of StaticTest object.
Can anyone here explain me how is that possible?
Thanks in advance for your help.
Regards,
Alain.

>
thread test1 creates its own stack and starts incrementing �i� starting at values 0. However, in the middle of incrementing, it gets kicked out by the OS (or JVM) into a �blocked� state to allow other threads to run. BUT before leaving the running state, test1 saves the stack state including the value of �i�.
>
Ok, now I understand, but then I have another question.
What is the difference between the code shown in my first post and the following where we create 2 instances of StaticTest class (which is not static in this case for sure).
How to decide (while coding) if it is better to use difference instances of class or not?
package test;
public class StaticTest {
 public StaticTest() {
 public void test (int i){ //Not static anymore
 while (i < 1000){
 System.out.println("i = " + i );
 i++;
}We create new instance in the Thread.
package test;
public class ThreadTester extends Thread {
 int x;
 public ThreadTester(int i) {
 x=i;
 public void run(){
StaticTest newInstance = new StaticTest(); //Create a new instance
 newInstance .test(x);
}Alain

Variables declared in static methods

Hi,
I've got a question. Are variables (primitive and Objects) declared inside
static methods stored in a same memory space or are the stored separately?
I'm creating a helper class that contains static methods that canno be placed in any object in my object map.
For example
public static String SampleMethod(String passedString)
String str = new String(passedString);
...do some more processing and sleeping
return str;
Let's say Object1 and Object2 make a call to SampleMethod. Object1 passes "Object1" and right before the Object1's SampleMethod returns str, Object2 makes a call passing "Object2". What would be the value of str for Object1's SampleMethodCall?
Thanks :)

If speaking about class members, then static members are stored in one place and are properties of the class, when non-staic members are stored in an object's memory and a properties of an object.
However in your sample it's not the case.
Local variables of a method are most likely allocated on registers or on stack (thus being rather properties of the call to a method).
Thus in your case calls to SampleMethod done by Object1 and Object2 simultaneously (if you managed to do this in two different threads) will use different memory (most likely in threads' own stacks).
As for calls to "new String" inside your method, the new string memory will be allocated dynamically each time the new operator is called, thus producing two different objects. The references to them will be stored in two local variables of two independent calls.
Finally, Object1 will get a copy of "Object1" and Object2 will get a copy of "Object2", as expected.
Vit

Static method decisions

Dear all experts,
I have got some problems understanding when to use static methods or passing the classes through constructor.
I have got a class which needs to be accessed by several classes and also the classes inside the classes etc....
Instead of passing classes around, should I just create a single static class which can be accessed by all the classes without needing to instantiate the class?
I found that, i particularly in doubt when there are classes like "TableParser", "PropertiesReader" etc which some classes deep down in the hierarchy need access to those classes...
Also, making the class static would it decrease the security of the whole program?? Say if i have got an encrytion class which does all the encrypt and decrypt, if i let it be static, isn't it easier to let people accessing the method? the same applies to properties editor etc??
Any help would be really appreciated.
Thx

thx again jverd... (remember the security question? :)
)I remember your id, but I didn't recall which thread(s) I had seen it in.
>
based on the understanding of what you said, do you
mean that, if i am only using a class to store or read
a setting file, it's ok to let it static? (so that all
classes can access it whenever they like without
passing the parser class to classes?)Um, again, you're terminology's a little off, so I'm not sure exactly what you mean, and even the description "store or read a seting file" could have a couple of interpretations.
For example....You read the file once, and the config data it constains is accessible throughout your app and never changes. This might be a candidate for a class that only had static methods, but it would be kind of inflexible. What if later some other part of your app, or some other library that you develop that your app is going to use, wants to get its configuration from a file. In that case, I might want to have a couple instances of that class around. One for the global config that reads one file, and another for the config for that library that might read another file.
I'd probably not even think about it as "reading a settings file." Rather, I'd see that as two parts: providing config settings to the app via a class, and reading a file to populate that class. The settings would exist independent of the fact that you can populate them from a file.
I'd think about how I want to use them and decide whether to instantiate the class or use static methods based on that. Separately, I'd think about how this class or an instance of it is gonna get popuated with data from outside the program.
I might decide to have different instances hold different sets of config data, and therefore use instance (non-static) methods to access the data in each of those instances, but I might register the instances--say by name, or maybe just in a list--and I could use a static method to acess the map or list: Config dbConfig = Config.getConfig("database"); Also, I wouldn't generally make a decsision on whether to use class methods or instance methods based on not having to pass a parameter.
If you're thinking "I'd like to use static because it's easier. Can I get away with it here," then you're viewing objects as a burden to be avoided, which kind of defeats the purpose of using OO techniques in the first place.

Help on calling static method in a multithreaded environment

Hi,
I have a basic question.. pls help and it is urgent.. plss
I have a class with a static method which does nothing other than just writing the message passed to a file. Now i have to call this static method from many threads..
What actually happens ???
Does all the thread start to execute the static method or one method executes while the other threads wait for the current thread to complete execution?. I am not talking about synchronizing the threads...my question is what happens when multiple threads call a static method??
Pls reply.. I need to design my project accordingly..
Thanks
Rajeev

HI Omar,
My doubt is just this..
I wanted to know what might happen if two threads try to access a static method.. Logically only one thread can use the method since it is only only copy... but i was wondering what might happens if f threads try to access the same static method.. My Situation is this.. I have a cache which is just a hash table which will be only one copy for the whole application.. No when i get a request I have to check if the id is avaible in the cache. if it is available i call method 1 if not i call method2. Now Ideally the cache should be a static object and the method to check the id in the cache will be a normal instance method..
I was just wondering what might happen if i make the method static.. If i can make it static i can can save a lot of space by not creating the object each time.. u know what i mean.. That y i wanted to know what happens..
Rajeev

Static methods vs instant methods

hi to all abap gurus
thanks in advance
all of the objects in the class can acess its its static attributes . and if u change the static attribute in an object the change is visible in all other objects in the calsssss.
can u pls expain this and tell the diffrence bewteen static and instance metod s?

Hi,
Instance Method
You can declare instance methods by using the METHODS statement. They play a very important role as they can access all of the attributes of a class and can trigger all of the events of the class.
Static Methods
You can declare static methods by using the CLASS-METHODS statement. They are important and can only access static attributes and trigger static events.
STATIC METHODS
CAN ONLY USE STATIC COMPONENTS IN THEIR IMPLEMENTATION PART
CAN BE CALLED USING THE CLASS
Static methods (also referred to as class methods) are called using CALL METHOD <classname>=><class_method>.
If you are calling a static method from within the class, you can omit the class name.
You access static attributes using <classname>=><class_attribute>
Regards,
Padmam.

Getting class in a static method

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