How to Load a class manually

Hello Friends,
I need a help regarding how to load a class manually.
i have the class name -- TestClass1
and Path - com.apps.classes
Thank you

Thank You------
I got the result
String classPath = com.apps.className;
Object obj = Class.forName(classPath).newInstance();

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What I mean is How to load/open java class file from jsp page?
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hi,
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File file = filechooser.getSelectedFile();
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You sure didn't need to post this twice.
http://forum.java.sun.com/thread.jsp?thread=522234&forum=31&message=2498659
When you post code, please use [code] and [/code] tags as described in Formatting Help on the message entry page. It makes it much easier to read and prevents accidental markup from array indices like [i].
You resolve this problem by ensuring the class is in the classpath and you refer to it by its full name.
§

How to Load a class file base on .class file name???

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1) Based on filename (d:\temp\bla.class), I want to load this bla.class and get the actual package of this class.
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package something.temp;
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Hi nikki96,
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import java.security.*;
import java.util.Enumeration;
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>
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>
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>
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Hai,
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I want to call a method from a class,which class is loaded dynamically.
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1.Detector.class (Applet) load in a html page, its class version is 1.5
2.It checks whether the JVM version of the browser is 1.5 / 1.6.
3.If it is 1.5, a new browser window popup and links to jre download page.
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roamer wrote:
..My question is, if the codes inside the Detector.class detects the JVM version is 1.6, HOW can I LOAD the Main.class (Applet) to the current scene?
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I have a java application that use another class in a jar file. And there is a class in the application's main class extends the class in the jar file. I have packaged the application into a jar file.
the directory structure :
foder [dist] : app.jar [lib]
foder [lib]: Library.jar
(I excute "java" cmd in folder "dist" )
Now i can run it, if i use command line option -Xbootclasspath/a:
"java -Xbootclasspath/a:lib/lib.jar -jar app.jar"
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Main.javapackage myapp;
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//Object    subobj = c.newInstance();
subclass.javapackage myapp;
subclass extends parentclass{
}parentclass.javapackage mylib;
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}the code Object    parentobj = c.newInstance(); can excute without problem . parentclass's constructor excuted.
but
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Object    subobj = c.newInstance();can not excute and without any exception throw out.
I used the "-verbose:class" option , the output is:
[Loaded java.lang.ClassFormatError from shared objects file] <---the last line
Thanks for reading and participating .
Please help me or point me to resources where I can read .
Sorry for my poor english.
thanks a lot .

The problem is that when a class wants to resolve a reference to another class (e.g. when a class fetches it's parent) it uses the classloader that loaded it, which is not necessarilly the classloader from which it was requested.
When you ask a standard classloader (e.g. URLClassLoader) for a class the first thing it tries is asking it's parent class loader. Only if the parent doesn't find the class does it try itself.
So, if a class is available to the system ClassLoader then even though you ask a URLClassLoader for it, it's the system ClassLoader which actually loads it and, hence, it's the system ClassLoader that class uses to resolve any references.
ClassLoaders generally form a kind or heirarchy and references can be made towards the root of the ClassLoader tree, but not in the other direction.
You would have to do something like have a small main class which sets up the classloader and make your real main class available only on the jars that the URLClassLoader adds to the classpath. That way the main class will have the URLClassLoader as its ClassLoader and will use it to get it's parent class.

How to load a class dynamically in the current/system class loader

I need to dynamically load a new jdbc driver jar to the current/system class loader... Please note that creating a new classloader will not help since the DriverManager refers to the systemclassloader itself.
Restarting the application by appending the jar to its classpath will solve the problem but I want to avoid doing this.

Did you then create a ClassLoader to load the JDBC
driver and then install it into the system as
directed by the JDBC specification (ie
Class.forName(someClassName))?
And then try to use it from a class loaded fromsome
other ClassLoader (i.e. the system class loader)?
If you did not try this please explain why not.O.K. I just looked at the source to
java.sql.DriverManager. I did not know what I was
talking about, as what I suggested above will not
work.
This is my new Idea:
Create a URLClassLoader to load the JDBC driver also
in this ClassLoader you need to place a helper class
that does the following:
public class Helper {
public Driver getJDBCDriver(String driverClassName,
String url) {
try {
Class.forName(driverClassName);
Driver d = DriverManager.getDriver(url);
return d;
catch(Exception ex) {
ex.printStackTrace();
return null;
}Now create an instance of the Helper class in the new
ClassLoader, and call its getJDBCDriver method to get
an instance of the driver (you will probably have to
create an interface in the root class loader that the
Helper implements so that you can easily call it).
Now from the root classloader you can make calls
directly to the returned Driver and bypass the
DriverManager and its restrictions on cross
ClassLoader access.
The only catch here is that you would have to call to
the returned Driver directly and not use the Driver
Manager.This sounds like will work but I did not want to load DriverManager in a new classloader.. I did a hack
I unzip the jar dynamically in a previously known location (which I included in my classpath when launching the app). The classLoader finds the class now though it did not exist when the app was launched !
A hack of-course but works eh ..

How to Load a class manually

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