What's a constructor?

What is a constructor?
When do I have to use it?
Thanks,
Rob

What are the bennefits of using a Constructor?
Or the disavantages of not using it?Your class might require some initialization for it to behave properly. The Constructor can do that initialization. For example, if you had a Person class, and each Person has a name field. If your design depends on each instance of Person having a valid name, you create a single Constructor that requires a String argument and uses that String as the name. This design means that an instance of Person can not be created without a name.
Alternately, Constructors can be used for convenience. If your design does not depend on a valid name, for example, then you could have both a no-argument Constructor and a Constructor that uses a String argument. The String argument Constructor provides a way to set the Person name at the time of creation instead of setting it later.

Similar Messages

Okay, now I know what to really ask

Hello, it's me again, please read the bottom.
public class Item implements Comparable
private int myId;
private int myInv;
public Item(int id, int inv)
myId = id;
myInv = inv;
public int getId(){ )
public int getInv(){ }
public int compareTo(Object otherObject){ }
public boolean equals(Object otherObject){ }
public String toString(){ }
public class Store
private Item[] myStore;
public Store(String fileName) { }
public void displayStore()
public String toString(){ }
public void doSort() { }
private void quickSort(Item[] list, int first, int last)
private void loadFile(String inFileName)
Yes. Like TheAmerican(a user) said, I really don't know, what those methods are supposed to be mean, and how they will function, nor any structures for those method.
I really don't know how that Store constructor will work.
I just had hope that someone can answer me one part and some other people the other part, or just the concept, big overview.
But i didn't make that clear at all because I was very busy..
so now,
I'm making it clear. All i need are some concepts. what those methods getId, getInv will do, and what would be the format(not the answer but some idea, because i'm really lost.) and what will that constructor store will do for me, and how the file50.txt array will fit in it.
Plus, I really need help on loading that file50.txt into my program and using it. I never learned it.
Again, you don't have to answer all the questions, if you know just know a part, then just answer that part. even if it's just half of that one answer, then just tell me the half.
I'm really desperate to see my way...
I was really furious about people who made fun of me for posting my homework, but it's all my fault.
I really hope, somebody can help me...
I'm so sorry that wasn't clear for my question, and now I kinda understand. please leave me good advices.

Stick to the original thread, and don't crosspost.
http://forum.java.sun.com/thread.jspa?threadID=699397
Please see my comments and links there.

Okay... Now I know what I should ask.

Hello, it's me again, please read the bottom.
public class Item implements Comparable
private int myId;
private int myInv;
public Item(int id, int inv)
myId = id;
myInv = inv;
public int getId(){ )
public int getInv(){ }
public int compareTo(Object otherObject){ }
public boolean equals(Object otherObject){ }
public String toString(){ }
public class Store
private Item[] myStore;
public Store(String fileName) { }
public void displayStore()
public String toString(){ }
public void doSort() { }
private void quickSort(Item[] list, int first, int last)
private void loadFile(String inFileName)
Yes. Like TheAmerican(a user) said, I really don't know, what those methods are supposed to be mean, and how they will function, nor any structures for those method.
I really don't know how that Store constructor will work.
I just had hope that someone can answer me one part and some other people the other part, or just the concept, big overview.
But i didn't make that clear at all because I was very busy..
so now,
I'm making it clear. All i need are some concepts. what those methods getId, getInv will do, and what would be the format(not the answer but some idea, because i'm really lost.) and what will that constructor store will do for me, and how the file50.txt array will fit in it.
Plus, I really need help on loading that file50.txt into my program and using it. I never learned it.
Again, you don't have to answer all the questions, if you know just know a part, then just answer that part. even if it's just half of that one answer, then just tell me the half.
I'm really desperate to see my way...
I was really furious about people who made fun of me for posting my homework, but it's all my fault.
I really hope, somebody can help me...
I'm so sorry that wasn't clear for my question, and now I kinda understand. please leave me good advices.

thank you jverdYou're welcome.
>
And, I think,,,
scsi what ever boy just abused me with profane
languages,
one i put a 'brat' was towarding myself so it doesn't
count , but
oh well
thanks anywaysI've unloaded more strongly for less serious "offenses" on occasion myself. For those of us that answer questions here regularly, there are certain behaviors that are irritating, and the more we see them, the more irritating they become, the more of a hair trigger we develop.
Don't take it personally, and don't let it stop you from posting your questions. Just try to see the message behind the flames. The same guy that rips you a new one for not formatting code one day may spend a dozen posts guiding you to a solution the next.

Use of constructor

hi could u explain the use of constructors....
in one class i have 2 constructors ..one is no argument constructor and second one is with arguments...... what these two constructors will do??....

The constructor that matches the method's invocation (no arg or arg) will be executed. See this tutorial for more explanation:
http://java.sun.com/docs/books/tutorial/java/data/objectcreation.html

Undefined Constructor for Polygon

Hello,
I have a undefined constructor error message for polygon in Eclipse and I cannot figure out why.
Initially I have this method and everything worked fine; public void drawing (Graphics g, List <int []> x_Points, List <int []>y_Points) {
          Graphics2D g2d = (Graphics2D) g;
          g2d.setColor(Color.blue);
          g2d.setStroke(new BasicStroke(1F));
          ArrayList<Polygon> list = new ArrayList<Polygon>();
           for( int p = 0; p < x_Points.size(); p++) {
               list.add(new Polygon(x_Points.get(p),y_Points.get(p),x_Points.get(p).length));
                }During the course of writing other methods, I found out that using List<List<Integer>> will be better than List<int []>, so I decided to modify the code above to:public void drawings(Graphics g, List <List<Integer>> x_Points, List <List<Integer>>y_Points) {
          Graphics2D g2d = (Graphics2D) g;
          g2d.setColor(Color.blue);
          g2d.setStroke(new BasicStroke(IF));
          ArrayList<Polygon> list = new ArrayList<Polygon>();
           for( int p = 0; p < x_Points.size(); p++) {
               list.add(new Polygon(x_Points.get(p),y_Points.get(p),x_Points.get(p).size()));
                } But I got this Error; The constructor Polygon(List<Integer>, List<Integer>, int) is undefined
Thanks,
Jona_T

The polygon constructor you are using accepts arrays of ints, not Lists. I think it will work if you change it to:
list.add(new Polygon(x_Points.get(p).toArray(new Integer[0]),y_Points.get(p).toArray(new Integer[0]),x_Points.get(p).size()));toArray converts the list to an array, which is what the Polygon constructor accepts, and the argument of an Integer array tells it to make an array of Integers instead of an array of Objects.

Using this with a Constructor??

What is explicit constructor invocation?
I can't really understand this. I've been reading this for many times but my dull head does not really understand..Please help..!!

http://java.sun.com/docs/books/jls/third_edition/html/classes.html#8.8.7.1

Constructor with no parameters

Greetings,
What is a constructor with no parameters?
Just started on my new lab today and most of its going pretty good. Except I can't get the compiler to go past the first part...which pretty much hangs up the rest. My instructions are to create a constructor with no parameters, and after doing some research I thought I did that. Would someone mind taking at look at this and help me understand what I'm not doing? Thanks.
I'm only suppose to use the three variables that I've already put in, but the first constructor doesn't want to use any of those.
public class Time
    // instance variables
    private int hour;
    private int minutes;
    private int seconds;
     * Default constructor for objects of class Time.
    public Time()
        Time();
    }

public class Time {
    private int hour;
    private int minutes;
    private int seconds;
    // no constructor typed
    public static void main(String[] args) {
        Time t1 = new Time(); // OK
        Time t2 = new Time(5, 5, 5); // error
}This is Ok for t1 because if you do not provide a default (no args) constructor, one will be supplied when it compiles.
public class Time {
    private int hour;
    private int minutes;
    private int seconds;
    public Time(int h, int m, int s) {
    public static void main(String[] args) {
        Time t1 = new Time(); // error
        Time t2 = new Time(5, 5, 5); // OK
}Now ok for t2 since you have provided a constrcutor but not ok for t1 as the default constructor will not be provided for you. Default constructor only provided if you do not provide one.
public class Time {
    private int hour;
    private int minutes;
    private int seconds;
    public Time() {}
    public Time(int h, int m, int s) {
    public static void main(String[] args) {
        Time t1 = new Time(); // OK
        Time t2 = new Time(5, 5, 5); // OK
}Now both t1 and t2 are ok since both constructors are been supplied.

Activatable object must provide an activation constructor error

Hi everybody,
while I'm trying to calling a simple activatable object, I got this error
rmi://localhost:1099/MyActivatableServer
Found a reference to the object that extend IMyRemoteInterface and Activatable
Invoking the remote method of this object
RemoteException
java.rmi.activation.ActivateFailedException: activation failed; nested exception is:
     java.rmi.activation.ActivationException: Activatable object must provide an activation constructor; nested exception is:
     java.lang.NoSuchMethodException: Progetto3.MyActivatableServer.<init>(java.rmi.activation.ActivationID, java.rmi.MarshalledObject)
     at sun.rmi.server.ActivatableRef.activate(ActivatableRef.java:285)
     at sun.rmi.server.ActivatableRef.invoke(ActivatableRef.java:114)
     at Progetto3.MyActivatableServer_Stub.chiamamiInRemoto(Unknown Source)
     at Progetto3.Client.run(Client.java:52)
     at Progetto3.Client.main(Client.java:78)
Caused by: java.rmi.activation.ActivationException: Activatable object must provide an activation constructor; nested exception is:
     java.lang.NoSuchMethodException: Progetto3.MyActivatableServer.<init>(java.rmi.activation.ActivationID, java.rmi.MarshalledObject)
     at sun.rmi.server.ActivationGroupImpl.newInstance(ActivationGroupImpl.java:273)
     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
     at java.lang.reflect.Method.invoke(Method.java:585)
     at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:294)
     at sun.rmi.transport.Transport$1.run(Transport.java:153)
     at java.security.AccessController.doPrivileged(Native Method)
     at sun.rmi.transport.Transport.serviceCall(Transport.java:149)
     at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:460)
     at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:701)
     at java.lang.Thread.run(Thread.java:595)
     at sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(StreamRemoteCall.java:247)
     at sun.rmi.transport.StreamRemoteCall.executeCall(StreamRemoteCall.java:223)
     at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:126)
     at java.rmi.activation.ActivationGroup_Stub.newInstance(Unknown Source)
     at sun.rmi.server.Activation$ObjectEntry.activate(Activation.java:1277)
     at sun.rmi.server.Activation$GroupEntry.activate(Activation.java:972)
     at sun.rmi.server.Activation$ActivatorImpl.activate(Activation.java:243)
     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
     at java.lang.reflect.Method.invoke(Method.java:585)
     at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:294)
     at sun.rmi.transport.Transport$1.run(Transport.java:153)
     at java.security.AccessController.doPrivileged(Native Method)
     at sun.rmi.transport.Transport.serviceCall(Transport.java:149)
     at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:460)
     at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:701)
     at java.lang.Thread.run(Thread.java:595)
     at sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(StreamRemoteCall.java:247)
     at sun.rmi.transport.StreamRemoteCall.executeCall(StreamRemoteCall.java:223)
     at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:126)
     at java.rmi.server.RemoteObjectInvocationHandler.invokeRemoteMethod(RemoteObjectInvocationHandler.java:179)
     at java.rmi.server.RemoteObjectInvocationHandler.invoke(RemoteObjectInvocationHandler.java:132)
     at $Proxy0.activate(Unknown Source)
     at java.rmi.activation.ActivationID.activate(ActivationID.java:96)
     at sun.rmi.server.ActivatableRef.activate(ActivatableRef.java:258)
     ... 4 more
Caused by: java.lang.NoSuchMethodException: Progetto3.MyActivatableServer.<init>(java.rmi.activation.ActivationID, java.rmi.MarshalledObject)
     at java.lang.Class.getConstructor0(Class.java:2647)
     at java.lang.Class.getDeclaredConstructor(Class.java:1953)
     at sun.rmi.server.ActivationGroupImpl$1.run(ActivationGroupImpl.java:228)
     at java.security.AccessController.doPrivileged(Native Method)
     at sun.rmi.server.ActivationGroupImpl.newInstance(ActivationGroupImpl.java:222)
     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
     at java.lang.reflect.Method.invoke(Method.java:585)
     at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:294)
     at sun.rmi.transport.Transport$1.run(Transport.java:153)
     at java.security.AccessController.doPrivileged(Native Method)
     at sun.rmi.transport.Transport.serviceCall(Transport.java:149)
     at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:460)
     at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:701)
     at java.lang.Thread.run(Thread.java:595)
I can't figure out what constructor it need, because there is already a default constructor in the remote object implementation.
do anybody have an idea?
I'm going to post the program code in the reply.

here is the client code
public class Client implements Runnable {
     private String server;
     private long ms;
     private String msg;
     public Client(String server, long ms, String msg) {
          //server address
          this.server = server;
          //time in ms need for the activatable object
          this.ms = ms;
          //the message to print out
          this.msg = msg;
          public void run() {
          //create a securitymanager
          System.setSecurityManager(new RMISecurityManager());
         try {
               String location = "rmi://" + server + "/MyActivatableServer";
               System.out.println(location);
               //lookup on server
               IMyRemoteInterface mri = (IMyRemoteInterface)Naming.lookup(location);
               System.out.println("Found a reference to the object that extend IMyRemoteInterface and Activatable ");
               int risultato = 0;
               System.out.println("Invoking the remote method of this object");
                //call the method "chiamamiInRemoto" of the remote activatable object
               risultato = mri.chiamamiInRemoto(ms, msg);
               System.out.println("Fine dell'invocazione remota");
               if (risultato != 0)
                    System.out.println("ok");
               else
                    System.out.println("no ok");
          } catch (MalformedURLException e) {
               System.out.println("MalformedUrlException");
               e.printStackTrace();
          } catch (RemoteException e) {
               System.out.println("RemoteException");
               e.printStackTrace();
          } catch (NotBoundException e) {
               System.out.println("NotBoundException");
               e.printStackTrace();
          } catch (AccessControlException e){
               System.out.println("AccessControlException");
               e.printStackTrace();
          } catch (Exception e){
               System.out.println("Other Exception");
               e.printStackTrace();
     public static void main(String[] args) {
          Client cliente = new Client("localhost:1099",150,"hello");
          cliente.run();
}the server interface that the activatable implements is simply
public interface IMyRemoteInterface extends Remote {
     public int chiamamiInRemoto(long ms, String msg) throws RemoteException;
}and the activatable object's implementation is
public class MyActivatableServer extends Activatable implements IMyRemoteInterface {
     //il threadpool per gestire le chiamate arrivate
     private final ExecutorService pool;
     //per accedere al variabile indice, bisogna prima sincronizzarsi su questo lock
     private Object objLock;
     //un indice che tiene conto di quanti thread sono stati creati per gestire l'invocazione del client
     private int indice;
     public MyActivatableServer(ActivationID id, int data)
               throws RemoteException {
          super(id, data);
          objLock = new Object();
          indice = 1;
          //il pool creato � di tipo CachedThreadPool, che aggiunge un nuovo thread al pool
          //nel caso in cui i thread presenti non siano disponibili per una nuova chiamata.
          pool = Executors.newCachedThreadPool();
     public int chiamamiInRemoto(long ms, String msg)
          throws RemoteException {
//doing something here and return an Integer number
}the setup java file is
public class MyActivatableServerSetup {
     public static void main(String[] args) {
          System.setSecurityManager(new RMISecurityManager());
          //create an instance of ActivationGroup
          Properties props = new Properties();
          props.put("java.security.policy","d:\\policy");
          System.out.println(props.getProperty("java.security.policy"));
          ActivationGroupDesc.CommandEnvironment ace = null;
          ActivationGroupDesc ActivationGruppo = new ActivationGroupDesc(props, ace);
          try {
               //registration
               ActivationGroupID agID = ActivationGroup.getSystem().registerGroup(ActivationGruppo);
               //location define l'URL where class are
               String location = "file:///d:\\progetti\\Progetto\\bin\\";
               //Other parameters need for the constructor of ActivationDesc
               MarshalledObject data = null;
               ActivationDesc desc = new ActivationDesc(agID,"Progetto3.MyActivatableServer",location,data);
               //Registration to rmid
               IMyRemoteInterface mri = (IMyRemoteInterface)Activatable.register(desc);
               System.out.println("obtain stub for MyActivatableServer");
               //Bind the stub
               Naming.rebind("MyActivatableServer", mri);
               System.out.println("Esportato MyActivatableServer");
          } catch (RemoteException e) {
               System.out.println("RemoteException al Setup");
               e.printStackTrace();
          } catch (UnknownGroupException e) {
               System.out.println("UnknownGroupException al Setup");
               e.printStackTrace();
          } catch (MalformedURLException e) {
               System.out.println("MalformedURLException al Setup");
               e.printStackTrace();
          } catch (ActivationException e) {
               System.out.println("ActivationException al Setup");
               e.printStackTrace();
          System.exit(0);
}I can start the rmiregistry and rmid without problem, I can't esecute the setup of activatable object without problem, but when I try esecuting the client, the activation constructor error appear.
I really can't figure out what is this constructor, doesn't I already implemented in my activatableServer yet? with public MyActivatableServer(ActivationID id, int data)
               throws RemoteException {thanks in advance for everybody.

IllegalArgumentException with Constructor.newInstance

Hi,
I am having problem in the following piece of code . Its giving exception at code line
Servant tieInstance = (Servant) tieConstructor.newInstance(constructorArgs);
Can you plz let me know what might be the problem.
private Servant createTie()
String className = getClassNameForTie();
className = className.substring(className.lastIndexOf(46) + 1, className.length() - 4);
String tieName = getTieClassPackage() + "." + className +
TIE_CLASSNAME_POSTFIX;
try
Class tieClass = Class.forName(tieName);
Constructor tieConstructor = tieClass.getDeclaredConstructors()[0];
Object constructorArgs[] = new Object[2];
constructorArgs[0] = this;
constructorArgs[1] = PDMEServer.getTheRootPOA();
System.out.println("00000 constructorArgs[0]= " + constructorArgs[0]);
System.out.println("11111 constructorArgs[1]= " + constructorArgs[1]);
Servant tieInstance = (Servant) tieConstructor.newInstance(constructorArgs);
return tieInstance;
catch(ClassNotFoundException ex)
MappingFaultHandler.unexpectedException(this, ex, false);
catch(IllegalAccessException ex)
MappingFaultHandler.unexpectedException(this, ex, false);
catch(InstantiationException ex)
MappingFaultHandler.unexpectedException(this, ex, false);
catch(InvocationTargetException ex)
MappingFaultHandler.unexpectedException(this, ex, false);
catch(IllegalArgumentException ex)
{ System.out.println("*********** IllegalArgumentException caught");
MappingFaultHandler.unexpectedException(this, ex, false);
return null;
}

what does the constructor for the class that getClassNameForTie() names look like?

Oracle.jbo.domain.Date and JavaDoc

Is there any javadoc for oracle.jbo.domain.Date etc?
If not then what is the constructor?
What format is the String passed in?....DD/MM/YY ???
Can you pass in a java.util.Date to the constructor?
Thanks,
Paul.

http://otn.oracle.com/jdeveloper/help/topic?inOHW=true&linkHelp=false&file=jar%3Afile%3A/u01/webapps/OHW/ohw-app/jdeveloper/helpsets/jdeveloper/reference/reference.zip!/bc4jdomorcldoc/oracle/jbo/domain/Date.html

ResourceBundle problem with IE7

Hi all,
I have problems getting the correct ResourceBundle from the Locale in my applet using IE7. It works with Firefox2 (and with IE6 as a user told me, I did not test this though). Can anyone help me with this? Below you see relevant code and the output in Firefox and IE7:
System.out.println("DisplayLanguage: "+currentLocale.getDisplayLanguage());
    res_bundle = ResourceBundle.getBundle("myResources.ApplicationResources", currentLocale);
    System.out.println("Locale in ResourceBundle: "+res_bundle.getLocale().toString());
    System.out.println("DisplayLanguage in ResourceBundle: "+res_bundle.getLocale().getDisplayLanguage());
Output in Firefox 2:
DisplayLanguage: Italienisch
Locale in ResourceBundle: it //correct
DisplayLanguage in ResourceBundle: Italienisch
Output in InternetExplorer 7:
DisplayLanguage: it_it //different from the Firefox output
Locale in ResourceBundle: de //incorrect, this is the default Locale
DisplayLanguage in ResourceBundle: Deutsch

Ok, this is apparently a JSP issue. The Language Code provided by request.getLocale() in the JSP is not the same for every browser:
in Firefox: de, it (this is what the Locale constructor needs: the ISO-639 language code)
in IE7, Safari: de_DE, it_IT
I don't know why this is the case, but now I can use a workaround (i.e. ignore the second part of the language code).
So, the problem is solved. However, I would be still interested in the reasons for these differences...
Thanks, Gonzberg

Qualifing to be an immutible object

Question: Is it possible to design an immutable object having final object references to mutable objects and still be 'viewed' as immutable.
From the book JAVA Concurrency in Practice by Brian Goetz the following statements are made (that have confused me a bit):
"Immutable objects ... can be safely accessed even when synchronization is not used to publish the object reference." (p.51)
"... if [an object's] final fields refer to mutable objects, synchronization is still required to access the state of the objects they refer to."(p.52) To me this states that this type of object is not considered immutable.
However, notice the final array object references to BigInteger[] from an example on page 49:
@Immutable
class OneValueCache {
    private final BigInteger lastNumber;
    private final BigInteger[] lastFactors;
    public OneValueCache( BigInteger i, BigInteger[] factors ) {
        lastNumber = i;
        lastFactors = Array.copyOf( factors, factors.length );
    public BigInteger[] getFactors( BigInteger i ) {
        if ( lastNumber == null || !lastNumber.equals( i ))
            return null;
        else
            return Arrays.copyOf( lastFactors, lastFactors.length );
} Can all of the bigInteger[] lastFactors be considered final since the array object reference is final? Or is the immutability allowed since lastFactors is isolated with Arrays.copyOf() in both the constructor and getFactors() function? Does isolation of mutable objects references using techniques such as object cloning allow the object design to be immutable?
Edited by: rbroersma on May 18, 2010 10:37 PM

ejp wrote:
So if the Object doesn't exist until the constructor returns what is the constructor is working on? Bringing the object into existence.He means, what is the constructor operating on or +manipulating, i.e. what is "this" referring to at that point? Because you can pass "this" to other methods as if it existed. And they can operate on it as if it existed... So if you can do all those things to an object that doesn't exist, what good is your definition of existence?

JTable configuration!! URGENT HELP

The table is being constructed dynamically and can change many times during the running time of the application.
What kind of constructor can I use and is there any website where I can examples of this?
Appreciate your help.

I always recommend writing your own table model for anything other than a trivial table; TableModel is an interface that's very easy to implement and having your own will allow you to grow the complexity of the table structure without getting confused.
It'll also help you to understand how JTable works!

Error creating Objects with Reflection

This is the code:
try{
     System.out.println("Restart - test 1 - sub == " + sub);
     c = Class.forName(sub);
     con = c.getDeclaredConstructor();
catch(NoSuchMethodException e){
     System.out.println("Unknown event type\t" + e);
}Output:
Restart - test 1 - sub == Mouse
Unknown event type     java.lang.NoSuchMethodException: Mouse.<init>()I have a Mouse class with a declared Constructor. Why can't it find the Constructor?

SquareBox wrote:
almightywiz wrote:
Your code is trying to find the default constructor for your Mouse class. If you don't have a default constructor specified, it will throw the exception you encountered. What does your constructor signature look like?
public Mouse(int weight){
     this.weight = weight;
}How do I get the Constructor if it contains parameters?This is answered in your other thread: Creating objects with relfections And you even marked it correct!
Please don't post the same question multiple times. It leads to people wasting their time duplicating each others' answers, and makes for a fractured discussion.
Edited by: jverd on Apr 26, 2011 3:59 PM

Global timer control

hi all-
I'm writing a video game and I have used timers all over the
place to make everything go. now I want to be able to pause the
game, completely. meaning, I need to stop and start all timer
instances at once, or globally.
so I created a Timer subclass called CustomTimer, put some
statics in there, came up with the attached code. now my problem is
that I'm pretty sure I've created a memory leak, in that the
instances array will just grow and wont allow or gc.
so, my question is, is there an "onDestroy()" method or
somesuch, that I can override, and use that moment to remove
instance refs from the instances array?
or, is there a smarter way to do this? an application object
w/ a pause method perhaps?
thanks

I'm not sure if I understand. You say this: "once the only
ref to the CustomTimer instance is in that array.", but aren't you
adding instances of CustomTimer to the instances array every time
you create a CustomTimer? That's what the CustomTimer constructor
is doing. That would imply that there are multiple instances of
CustomTimer in the instances array.
In any case, you could add this to CustomTimer:
public static function removeTimer(timer:Timer):void
var len:int = instances.length;
for (var i:int; i<len; i++)
if (timer==instances
instances = instances.splice;
return;
}

What's a constructor?

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