How to instantiate a class from a different package?

I am trying to instatiate a class in a package: a.b.c from another class in a different package: d.e.f
How could I do so?
I've already been trying many things but didn't manage to get it to work...

Did you include both jar files in your classpath? Use
the -cp option of the java interpreter to specify your
classpath.Well, I tried adding the jar file to the classpath, without any success...
String path = getClass().getProtectionDomain().getCodeSource().getLocation().toString();
               String finpath = "";
               for(int i=6;i<path.length();i++)
                    finpath = finpath+path.charAt(i);
               System.setProperty("java.class.path",System.getProperty("java.class.path")+";"+finpath+"mm.mysql-2.0.14-bin.jar/");That's what I did and it didn't work...
If you "unpack" the jars see if there is the correct
packages-folders symmetry...Yes, the classes are in the package-folders they should be in..

Similar Messages

How to instantiate a .class from a JSP?

Hi,
probably it's a simple problem, byt I'm new in JSP and I couldn't work it out.
I'm converting a SSJS Netscape Application to JSP. My needing is to write a Java .class containing only static methods, to call them from the JSP pages.
For trying, I wrote a simple class that I call from a JSP page, but I get this error:
Error: 500
Location: /JSP24H/cap01/Simple2.jsp
Internal Servlet Error:
org.apache.jasper.JasperException: Unable to compile class for
JSPC:\tomcat\work\localhost_8080%2FJSP24H\_0002fcap_00030_00031_0002fSimple_00032_0002ejspSimple2_jsp_0.java:80:
Incompatible type for =. Can't convert void to java.lang.String.
v = GenFunction.messaggio();
^
This is the JSP instantiating the Java class:
<HTML>
<HEAD><TITLE>A Simple JSP</TITLE></HEAD>
<BODY>
<FONT COLOR="blue" FACE="Trebuchet">
<CENTER>
<%@ page import = "GenFunction" %>
<% out.println("My name is Charly !" + "<br>"); %>
<%
String v = " ";
v = GenFunction.messaggio();
out.println( v );
%>
</CENTER>
</FONT>
</BODY>
</HTML>
And this is the class instantiated from JSP:
public class GenFunction {
public static void main (String args[]) {
public static String messaggio() {
String a;
a = " Hello world !";
return a;
In order to be sure about what I'm doing, I opened a DOS window and I called the class within the following:
public class call_Class {
public static void main (String args[])
String v;
GenFunction x = new GenFunction();
v = x.messaggio();
System.out.println(v);
When I instantiate the class from DOS it's all right, why not from JSP. It seems to be returning a void value (I tried with casting too but without success).
Thanks !

Do you have multiple versions of classes in the server CLASSPATH somehwhere? If you have changed the class, and not bounced the server, try bouncing the server(may be using cached class)
-Mak

.How to instantiate the innerclass from another class with coded eg.

How to instantiate the innerclass from another class(both for static & non static) please give me an eg with coding.

It's just a preference, but I like writing factory methods:
public class Outer {
    public class Inner {}
    public static class StaticInner {}
    public Inner innerInstance() {
        return new Inner();
    public static StaticInner staticInnerInstance() {
        return new StaticInner();
    public static void main(String[] args) {
        Outer.StaticInner si = Outer.staticInnerInstance();
        Outer outer = new Outer();
        Outer.Inner i = outer.innerInstance();
}Often, for me, the inner class implements an interface, and the factory method
lets you hide the implementation class:
public class Outer {
    private class Inner implements Runnable {
        public void run() {}
    public Runnable runnerInstance() {
        return new Inner();
    public static void main(String[] args) {
        Outer outer = new Outer();
        Runnable r = outer.runnerInstance();
}

Invoke a method in one class from a different class

I am working on a much larger project, but to keep this simple, I wrote out a little test that would convey the over all theory of the program.
What I am doing is starting out with a 2 JFrames and a Class. When the program is launched, the first JFrame opens. In this JFrame is a label and a button. When the button is clicked, the second JFrame opens. This JFrame has a textField and a button. The user puts the text in the textField and presses the button. When the button is pushed, I want the text that was just put in the textField, to be displayed in the first JFrame's label. I am trying to invoke a method in the first JFrame from the second, but nothing happens. I have also tried making the Class extend from JFrame1 and invoke it from there, but no luck. So, how do I invoke a method in a class from a different class?
JFrame1 (I omitted the layout part. I made this in Netbeans so its pretty long)
public class NewJFrame1 extends javax.swing.JFrame {
     private NewClass1 nC = new NewClass1();
     /** Creates new form NewJFrame1 */
     public NewJFrame1() {
          initComponents();
          jLabel1.setText("Chuck");
     public void setLabels()
          jLabel1.setText(nC.getName());
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
     NewJFrame2 j2 = new NewJFrame2();
     j2.setVisible(true);The class
public class NewClass1 {
     public static String name;
     public NewClass1()
     public NewClass1(String n)
          name = n;
     public String getName()
          return name;
     public void setName(String n)
          name = n;
}The second jFrame
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
     NewClass1 nC = new NewClass1();
     NewJFrame1 nF = new NewJFrame1();
     nC.setName(jTextField1.getText());
     nF.setLabels();
     System.out.println(nC.getName());At this point I am begging for help. I have been trying for days to figure this out, and I just feel like I am not getting anywhere.
Thanks

So, how do I invoke a method in a class from a different class?Demo:
public class Main {
    public static void main(String [] args) {
     Test1 t1 = new Test1();
     Test2 t2 = new Test2();
     int i = t1.method1();
     String s = t2.method2(i);
     System.out.println(s);
class Test1 {
    public int method1() {
     return 10;
class Test2 {
    public String method2(int i) {
     if (i == 10)
         return "ten";
     else
         return "nothing";
}Output is "ten".
Edited by: newark on May 28, 2008 10:55 AM

How can I transfer songs from two different itunes?

I want to transfer songs from my brother's itunes library to my shuffle, but when I plug it in his computer, a message saying that his library is not linked to my library (or something to that extent) and whether I would like to replace the songs. If I click yes, all my existing songs are replaced with HIS songs. If I click on NO, the Shuffle icon does not appear at all and I cannot transfer any of his songs to my shuffle. How can I transfer songs from two different computers into my shuffle without replacing any of my existing music?
Shuffle Windows XP
Windows XP

You'll have to setup your iPod to manual instead of automatic update (I'm not sure, though, if it works with the Shuffle as well).
Alexander.

How to import a class not in the package from a package

how to import a class not in the package from a package?

http://java.sun.com/docs/books/tutorial/java/interpack/usepkgs.html

How can i import tables from a different schema into the existing relational model... to add these tables in the existing model? plss help

how can i import tables from a different schema into the existing relational model... to add these tables in the existing relational/logical model? plss help
note; I already have the relational/logical model ready from one schema... and I need to add few more tables to this relational/logical model
can I import the same way as I did previously??
but even if I do the same how can I add it in the model?? as the logical model has already been engineered..
please help ...
thanks

Hi,
Before you start, you should probably take a backup copy of your design (the .dmd file and associated folder), in case the update does not work out as you had hoped.
You need to use Import > Data Dictionary again, to start the Data Dictionary Import Wizard.
In step 1 use a suitable database connection that can access the relevant table definitions.
In step 2 select the schema (or schemas) to import. The "Import to" field in the lower left part of the main panel allows you to select which existing Relational Model to import into (or to specify that a new Relational Model is to be created).
In step 3 select the tables to import. (Note that if there are an Foreign Key constraints between the new tables and any tables you had previously imported, you should also include the previous tables, otherwise the Foreign Key constraints will not be imported.)
After the import itself has completed, the "Compare Models" dialog is displayed. This shows the differences between the model being imported and the previous state of the model, and allows you to select which changes are to be applied.
Just selecting the Merge button should apply all the additions and changes in the new import.
Having updated your Relational Model, you can then update your Logical Model. To do this you repeat the "Engineer to Logical Model". This displays the "Engineer to Logical Model" dialog, which shows the changes which will be applied to the Logical Model, and allows you to select which changes are to be applied.
Just selecting the Engineer button should apply all the additions and changes.
I hope this helps you achieve what you want.
David

HT4061 How do I consolidate purchases from two different ids that are on the same bank account, and eliminate the extra id without losing any purchases?

How do I consolidate purchases from two different ids that are on the same bank account, and eliminate the extra id without losing any purchases? I want my music to match on both ipad and computer.

Purchases are forever tied to the AppleID they were bought with. There is currently no way to consolidate AppleIDs. Sorry.

HT204053 My ipad stores my documents on iCloud. How can I find them from a different computer, as I used to do by using a memory stick on my old PC etc ?

My ipad stores my documents in iCloud. How can I find them from a different computer? I used to use a memory stick and could work on my documents on any computer and want to have a replacement system using documents created on my ipad - I can't use a memory stick with it.

How do you know that they are on iCloud, the iPad can (and does) save locally. If they are on iCloud they will be accessible via the application that created them (Pages, Numbers etc) and can be reached from any computer with iCloud access by logging to iCloud.com. But you did that and stated that they are not there, so what makes you think that they are?

HT204074 How do I download apps from a different one of my apple id's?

How do I download apps from a different one of my apple id's? Would I change apple ID's on IPad that I want download app on? Do you lose music, apps when you switch from one apple ID to another?

Sign out of the store, and sign back in with the other ID. Nothing gets lost.

How to load java class from jsp page?

hi all!
Does anyone know how to load java class from jsp page?
I try to load java class from jsp page.
Is it possible to load java class fom jsp page?
thanks and have a good day!

What I mean is How to load/open java class file from jsp page?
I think we can open Applet from jsp page by using
<applet code=helloApplet.class width=100 height=100>
</applet>
but, how to open java class which is an application made by Frame?
thanks and have a good day

How to extend a class from super package?

Say I have a dir a\
in dir a\ there is a dir b\
in b\ there is a class called DerivedClass
in a\ there is a class called ExtendedClass
how do I extend ExtendedClass from DerivedClass?

package a.b;
import a.ExtendedClass;
public class DerivedClass extends ExtendedClass{
    //define class members
This is interesting. But the question is, how does java know where is package b??     By the classpath variable - the classpath is set to one directory above 'a'. When you say
     a.ExtendedClass, since the classpath is set to the immediate parent of a, it searches the child directories
     for a directory called 'a' and upon finding it, searches for a .class file 'ExtendedClass'.
     Similarly when you say a.b.DerivedClass, the search begins in the parent directory for a directory called a and then
     a directory 'b' inside it on finding which it searches for DerivedClass.class
Alternatively you could have defined DerivedClass to be in package 'b'.
     package b; //note the difference. Its b and not a.b
     import a.ExtendedClass;
     public class DerivedClass extends ExtendedClass{
         //define class members
     }in which case, you should set the classpath to
1. a's parent directory
2. a itself
The parent directory cp is still required to locate a.ExtendedClass
The fully qualified name of DerivedClass is b.DerivedClass
Thus if #1 alone were present, since 'b' is not directly inside the parent directory,
b.DerivedClass would never be found
Hence the #2 is required-the search should start from the directory 'a' (as directory 'b' is inside 'a').
therefore, a package is a directory.No, package is a very java specific thing and though logically package names should match directory names, they
arent the same.
cheers,
ram.

How do I calculate days from two different dates?

Hi all,
How do I calculate days from two different dates?
my requirement is to pass the number of days to target field from two dates.
Current date : 14/04/2010
Standard date: 01/01/1957 is the standard = day 0
Is it possible in graphical mapping with out udf?
Plz help me on this I have donu2019t have much knowledge on JAVA.
Thanks

Hi Yadav,
Probably this is not the correct forum for XI / PI .
You can post the same to...
Process Integration (PI) & SOA Middleware
Hope this helps.
Regards
Raj

How do I calculate days from two different dates in XI/PI?

Hi all,
How do I calculate days from two different dates in XI/PI?
my requirement is to pass the number of days to target field from two dates.
Current date : 14/04/2010
Standard date: 01/01/1957 is the standard = day 0
Is it possible in graphical mapping with out udf?
Plz help me on this I have donu2019t have much knowledge on JAVA.
Thanks

Hi Yadav,
Probably this is not the correct forum for XI / PI .
You can post the same to...
Process Integration (PI) & SOA Middleware
Hope this helps.
Regards
Raj

How can I use music from two different iTunes accounts?

how can I use music from two different iTunes accounts?

If you mean iTunes Store accounts, there's really nothing for you to do. Just add the tracks to the iTunes library and play them. Music purchased prior to late-2009 will been to be authorized, though. Pull down Store > Authorize... and type the credentials of the Apple ID used to buy the tracks.
If you mean something else, please describe in more detail.

How to instantiate a class from a different package?

Similar Messages

Maybe you are looking for