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I have the following code. The problem is it always display a null
value. It will not successfully set the Name. THanks.

import java.lang.reflect.Method;


public class dynamicloader {

private String name = "";


public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public void load() {
Class c = this.getClass();
Object newobj = null;
try {
newobj = c.newInstance();
} catch (Exception e) {
System.out.println(e);
}

try {
Method m = c.getMethod("setName", new Class[]{String.class});
String result = (String) m.invoke(newobj,new Object[]{"My name"});
System.out.println("Result: " + result);
} catch (Exception e) {
System.out.println(e);
}
}

public static void main(String[] args) {
dynamicloader dl = new dynamicloader();
dl.load();
}
}

Hi,

wrote:
> public class dynamicloader {
> ...
> public void setName(String name) {
> this.name = name;
> }
> ...
> Method m = c.getMethod("setName", new Class[]{String.class});
> String result = (String) m.invoke(newobj,new Object[]{"My name"});
> System.out.println("Result: " + result);

Take a look at your code again (I snipped everything except the
important lines) and think about it.

What do you expect?

Hint: What is the return type of the method you are invoking?

Ciao,
Ingo

wrote:
> I have the following code. The problem is it always display a null
> value. It will not successfully set the Name. THanks.

> public void setName(String name) {

> Method m = c.getMethod("setName", new Class[]{String.class});
> String result = (String) m.invoke(newobj,new Object[]{"My name"});
> System.out.println("Result: " + result);

You have displayed the return value from setName. setName does not
return a value.

Reflection is confusing and error-prone. It's best avoided.

Tom Hawtin

On Jun 27, 11:26 am, Tom Hawtin <use...@tackline.plus.com> wrote:
> jan.reb...@gmail.com wrote:
> > I have the following code. The problem is it always display a null
> > value. It will not successfully set the Name. THanks.
> > public void setName(String name) {
> > Method m = c.getMethod("setName", new Class[]{String.class});
> > String result = (String) m.invoke(newobj,new Object[]{"My name"});
> > System.out.println("Result: " + result);
>
> You have displayed the return value from setName. setName does not
> return a value.
>
> Reflection is confusing and error-prone. It's best avoided.
>
> Tom Hawtin

OMG... is this "self modifying code"?