reflection problem

X

xareon

hi all, i got a problem with this bunch of code:

Code: 
Manager boss = new Manager("Paul Brown", 1000, 500);

Class c = boss.getClass();

try
{
Field field = c.getField("bonus");

Integer newBonus = field.getInt(boss);
newBonus = newBonus + 200;
field.setInt(boss, newBonus);

}
catch(NoSuchFieldException nsfe)
{
System.out.println(nsfe.getMessage());
nsfe.printStackTrace();
}
catch(IllegalAccessException iae)
{
System.out.println(iae.getMessage());
iae.printStackTrace();
}

i got a class Manager with a public (otherwise i'd get a
NoSuchFieldException) Integer bonus field. i'd like to modify it via
reflection, but i get an error at this point:

Integer newBonus = field.getInt(boss);

Code: 
Exception in thread "main" java.lang.IllegalArgumentException:
Attempt to get java.lang.Integer field "dynamicbinding.Manager.bonus"
with illegal data type conversion to int
at
sun.reflect.UnsafeFieldAccessorImpl.newGetIllegalArgumentException(Unknown
Source)
at
sun.reflect.UnsafeFieldAccessorImpl.newGetIntIllegalArgumentException(Unknown
Source)
at sun.reflect.UnsafeObjectFieldAccessorImpl.getInt(Unknown Source)
at java.lang.reflect.Field.getInt(Unknown Source)
at reflection.Main.main(Main.java:30)

illegal data type conversion to int? what does it mean? how can i fix
this? thank you all :)
 
D

Daniel Pitts

hi all, i got a problem with this bunch of code:

Code: 
Manager boss = new Manager("Paul Brown", 1000, 500);

Class c = boss.getClass();

try
{
Field field = c.getField("bonus");

Integer newBonus = field.getInt(boss);
newBonus = newBonus + 200;
field.setInt(boss, newBonus);

}

catch(NoSuchFieldException nsfe)
{
System.out.println(nsfe.getMessage());
nsfe.printStackTrace();}

catch(IllegalAccessException iae)
{
System.out.println(iae.getMessage());
iae.printStackTrace();}

i got a class Manager with a public (otherwise i'd get a
NoSuchFieldException) Integer bonus field. i'd like to modify it via
reflection, but i get an error at this point:

Integer newBonus = field.getInt(boss);

Code: 
Exception in thread "main" java.lang.IllegalArgumentException:
Attempt to get java.lang.Integer field "dynamicbinding.Manager.bonus"
with illegal data type conversion to int
at
sun.reflect.UnsafeFieldAccessorImpl.newGetIllegalArgumentException(Unknown
Source)
at
sun.reflect.UnsafeFieldAccessorImpl.newGetIntIllegalArgumentException(Unknown
Source)
at sun.reflect.UnsafeObjectFieldAccessorImpl.getInt(Unknown Source)
at java.lang.reflect.Field.getInt(Unknown Source)
at reflection.Main.main(Main.java:30)

illegal data type conversion to int? what does it mean? how can i fix
this? thank you all :)
Click to expand...

getInt returns (int), where as your Bonus value is an Integer.

You can either change the type of your bonus to int, or you can use
Integer newBonus = (Integer)field.get(boss);


Although, I'm curious why you wish to use Reflection. If your project
is simply to learn more about reflection, thats fine, but usually
using reflection for this sort of thing is a Bad Idea (TM). Perhaps
if you shared your goal with the group, we could suggest a better way.
 
X

xareon

hi all, i got a problem with this bunch of code:
Click to expand...
Code: 
Manager boss = new Manager("Paul Brown", 1000, 500);[/QUOTE]
[QUOTE]
Class c = boss.getClass();[/QUOTE]
[QUOTE]
try
{
Field field = c.getField("bonus");[/QUOTE]
[QUOTE]
Integer newBonus = field.getInt(boss);
newBonus = newBonus + 200;
field.setInt(boss, newBonus); 

catch(NoSuchFieldException nsfe)
{
System.out.println(nsfe.getMessage());
nsfe.printStackTrace();}[/QUOTE]
[QUOTE]
catch(IllegalAccessException iae)
{
System.out.println(iae.getMessage());
iae.printStackTrace();} [QUOTE]
Click to expand...

i got a class Manager with a public (otherwise i'd get a
NoSuchFieldException) Integer bonus field. i'd like to modify it via
reflection, but i get an error at this point:
Click to expand...
Integer newBonus = field.getInt(boss);
Click to expand...
Code: 
Exception in thread "main" java.lang.IllegalArgumentException:
Attempt to get java.lang.Integer field "dynamicbinding.Manager.bonus"
with illegal data type conversion to int
at
sun.reflect.UnsafeFieldAccessorImpl.newGetIllegalArgumentException(Unknown
Source)
at
sun.reflect.UnsafeFieldAccessorImpl.newGetIntIllegalArgumentException(Unknown
Source)
at sun.reflect.UnsafeObjectFieldAccessorImpl.getInt(Unknown Source)
at java.lang.reflect.Field.getInt(Unknown Source)
at reflection.Main.main(Main.java:30)
Click to expand...
illegal data type conversion to int? what does it mean? how can i fix
this? thank you all :)
Click to expand...

getInt returns (int), where as your Bonus value is an Integer.

You can either change the type of your bonus to int, or you can use
Integer newBonus = (Integer)field.get(boss);

Although, I'm curious why you wish to use Reflection. If your project
is simply to learn more about reflection, thats fine, but usually
using reflection for this sort of thing is a Bad Idea (TM). Perhaps
if you shared your goal with the group, we could suggest a better way.[/QUOTE]

thank you man. although it sounds me funky to get an error with the
int/Integer assignaments (wrapper classes shouldn't give such
problems), i've tried your solution, and this one too:

int newBonus = f.getInt(boss);

but i keep on getting the same error at the same line. and finally
yes, my project is simply to learn more about reflection. i know i
could have simply done this via standard set/get methods :)
plus, to allow a pure OO programming, i'd avoid to change the type of
bonus from Integer to int :)
 
X

xareon

hi all, i got a problem with this bunch of code:
Click to expand...
Code: 
Manager boss = new Manager("Paul Brown", 1000, 500);[/QUOTE]
[QUOTE]
Class c = boss.getClass();[/QUOTE]
[QUOTE]
try
{
Field field = c.getField("bonus");[/QUOTE]
[QUOTE]
Integer newBonus = field.getInt(boss);
newBonus = newBonus + 200;
field.setInt(boss, newBonus); 

catch(NoSuchFieldException nsfe)
{
System.out.println(nsfe.getMessage());
nsfe.printStackTrace();}[/QUOTE]
[QUOTE]
catch(IllegalAccessException iae)
{
System.out.println(iae.getMessage());
iae.printStackTrace();} [QUOTE]
Click to expand...

i got a class Manager with a public (otherwise i'd get a
NoSuchFieldException) Integer bonus field. i'd like to modify it via
reflection, but i get an error at this point:
Click to expand...
Integer newBonus = field.getInt(boss);
Click to expand...
Code: 
Exception in thread "main" java.lang.IllegalArgumentException:
Attempt to get java.lang.Integer field "dynamicbinding.Manager.bonus"
with illegal data type conversion to int
at
sun.reflect.UnsafeFieldAccessorImpl.newGetIllegalArgumentException(Unknown
Source)
at
sun.reflect.UnsafeFieldAccessorImpl.newGetIntIllegalArgumentException(Unknown
Source)
at sun.reflect.UnsafeObjectFieldAccessorImpl.getInt(Unknown Source)
at java.lang.reflect.Field.getInt(Unknown Source)
at reflection.Main.main(Main.java:30)
Click to expand...
illegal data type conversion to int? what does it mean? how can i fix
this? thank you all :)
Click to expand...

getInt returns (int), where as your Bonus value is an Integer.

You can either change the type of your bonus to int, or you can use
Integer newBonus = (Integer)field.get(boss);

Although, I'm curious why you wish to use Reflection. If your project
is simply to learn more about reflection, thats fine, but usually
using reflection for this sort of thing is a Bad Idea (TM). Perhaps
if you shared your goal with the group, we could suggest a better way.[/QUOTE]

thank you man. although it sounds me funky to get an error with the
int/Integer assignaments (wrapper classes shouldn't give such
problems), i've tried your solution, and this one too:

int newBonus = f.getInt(boss);

but i keep on getting the same error at the same line. and finally
yes, my project is simply to learn more about reflection. i know i
could have simply done this via standard set/get methods :)
plus, to allow a pure OO programming, i'd avoid to change the type of
bonus from Integer to int :)
 
X

xareon

On Jul 25, 7:33 am, (e-mail address removed) wrote:
hi all, i got a problem with this bunch of code:
Code: 
Manager boss = new Manager("Paul Brown", 1000, 500); 
Class c = boss.getClass(); 
try
{
Field field = c.getField("bonus"); 
Integer newBonus = field.getInt(boss);
newBonus = newBonus + 200;
field.setInt(boss, newBonus); 
} 
catch(NoSuchFieldException nsfe)
{
System.out.println(nsfe.getMessage());
nsfe.printStackTrace();} 
catch(IllegalAccessException iae)
{
System.out.println(iae.getMessage());
iae.printStackTrace();}
i got a class Manager with a public (otherwise i'd get a
NoSuchFieldException) Integer bonus field. i'd like to modify it via
reflection, but i get an error at this point:
Integer newBonus = field.getInt(boss);
Code: 
Exception in thread "main" java.lang.IllegalArgumentException:
Attempt to get java.lang.Integer field "dynamicbinding.Manager.bonus"
with illegal data type conversion to int
at
sun.reflect.UnsafeFieldAccessorImpl.newGetIllegalArgumentException(Unknown
Source)
at
sun.reflect.UnsafeFieldAccessorImpl.newGetIntIllegalArgumentException(Unknown
Source)
at sun.reflect.UnsafeObjectFieldAccessorImpl.getInt(Unknown Source)
at java.lang.reflect.Field.getInt(Unknown Source)
at reflection.Main.main(Main.java:30)
illegal data type conversion to int? what does it mean? how can i fix
this? thank you all :)
Click to expand...
Click to expand...
getInt returns (int), where as your Bonus value is an Integer.
Click to expand...
You can either change the type of your bonus to int, or you can use
Integer newBonus = (Integer)field.get(boss);
Click to expand...
Although, I'm curious why you wish to use Reflection. If your project
is simply to learn more about reflection, thats fine, but usually
using reflection for this sort of thing is a Bad Idea (TM). Perhaps
if you shared your goal with the group, we could suggest a better way.
Click to expand...

thank you man. although it sounds me funky to get an error with the
int/Integer assignaments (wrapper classes shouldn't give such
problems), i've tried your solution, and this one too:

int newBonus = f.getInt(boss);

but i keep on getting the same error at the same line. and finally
yes, my project is simply to learn more about reflection. i know i
could have simply done this via standard set/get methods :)
plus, to allow a pure OO programming, i'd avoid to change the type of
bonus from Integer to int :)
Click to expand...


ty, i found the problem: it was just that getInt() method returns an
int, while my field was an Integer. i should have used

Integer newBonus = (Integer)f.get(boss);

get returns an object, that i just cast to Integer. sometimes i feel
so stupid :x
 
X

xareon

On Jul 25, 7:33 am, (e-mail address removed) wrote:
hi all, i got a problem with this bunch of code:
Code: 
Manager boss = new Manager("Paul Brown", 1000, 500); 
Class c = boss.getClass(); 
try
{
Field field = c.getField("bonus"); 
Integer newBonus = field.getInt(boss);
newBonus = newBonus + 200;
field.setInt(boss, newBonus); 
} 
catch(NoSuchFieldException nsfe)
{
System.out.println(nsfe.getMessage());
nsfe.printStackTrace();} 
catch(IllegalAccessException iae)
{
System.out.println(iae.getMessage());
iae.printStackTrace();}
i got a class Manager with a public (otherwise i'd get a
NoSuchFieldException) Integer bonus field. i'd like to modify it via
reflection, but i get an error at this point:
Integer newBonus = field.getInt(boss);
Code: 
Exception in thread "main" java.lang.IllegalArgumentException:
Attempt to get java.lang.Integer field "dynamicbinding.Manager.bonus"
with illegal data type conversion to int
at
sun.reflect.UnsafeFieldAccessorImpl.newGetIllegalArgumentException(Unknown
Source)
at
sun.reflect.UnsafeFieldAccessorImpl.newGetIntIllegalArgumentException(Unknown
Source)
at sun.reflect.UnsafeObjectFieldAccessorImpl.getInt(Unknown Source)
at java.lang.reflect.Field.getInt(Unknown Source)
at reflection.Main.main(Main.java:30)
illegal data type conversion to int? what does it mean? how can i fix
this? thank you all :)
Click to expand...
Click to expand...
getInt returns (int), where as your Bonus value is an Integer.
Click to expand...
You can either change the type of your bonus to int, or you can use
Integer newBonus = (Integer)field.get(boss);
Click to expand...
Although, I'm curious why you wish to use Reflection. If your project
is simply to learn more about reflection, thats fine, but usually
using reflection for this sort of thing is a Bad Idea (TM). Perhaps
if you shared your goal with the group, we could suggest a better way.
Click to expand...

thank you man. although it sounds me funky to get an error with the
int/Integer assignaments (wrapper classes shouldn't give such
problems), i've tried your solution, and this one too:

int newBonus = f.getInt(boss);

but i keep on getting the same error at the same line. and finally
yes, my project is simply to learn more about reflection. i know i
could have simply done this via standard set/get methods :)
plus, to allow a pure OO programming, i'd avoid to change the type of
bonus from Integer to int :)
Click to expand...


ty, i found the problem: it was just that getInt() method returns an
int, while my field was an Integer. i should have used

Integer newBonus = (Integer)f.get(boss);

get returns an object, that i just cast to Integer. sometimes i feel
so stupid :x
 
X

xareon

On Jul 25, 7:33 am, (e-mail address removed) wrote:
hi all, i got a problem with this bunch of code:
Code: 
Manager boss = new Manager("Paul Brown", 1000, 500); 
Class c = boss.getClass(); 
try
{
Field field = c.getField("bonus"); 
Integer newBonus = field.getInt(boss);
newBonus = newBonus + 200;
field.setInt(boss, newBonus); 
} 
catch(NoSuchFieldException nsfe)
{
System.out.println(nsfe.getMessage());
nsfe.printStackTrace();} 
catch(IllegalAccessException iae)
{
System.out.println(iae.getMessage());
iae.printStackTrace();}
i got a class Manager with a public (otherwise i'd get a
NoSuchFieldException) Integer bonus field. i'd like to modify it via
reflection, but i get an error at this point:
Integer newBonus = field.getInt(boss);
Code: 
Exception in thread "main" java.lang.IllegalArgumentException:
Attempt to get java.lang.Integer field "dynamicbinding.Manager.bonus"
with illegal data type conversion to int
at
sun.reflect.UnsafeFieldAccessorImpl.newGetIllegalArgumentException(Unknown
Source)
at
sun.reflect.UnsafeFieldAccessorImpl.newGetIntIllegalArgumentException(Unknown
Source)
at sun.reflect.UnsafeObjectFieldAccessorImpl.getInt(Unknown Source)
at java.lang.reflect.Field.getInt(Unknown Source)
at reflection.Main.main(Main.java:30)
illegal data type conversion to int? what does it mean? how can i fix
this? thank you all :)
Click to expand...
Click to expand...
getInt returns (int), where as your Bonus value is an Integer.
Click to expand...
You can either change the type of your bonus to int, or you can use
Integer newBonus = (Integer)field.get(boss);
Click to expand...
Although, I'm curious why you wish to use Reflection. If your project
is simply to learn more about reflection, thats fine, but usually
using reflection for this sort of thing is a Bad Idea (TM). Perhaps
if you shared your goal with the group, we could suggest a better way.
Click to expand...

thank you man. although it sounds me funky to get an error with the
int/Integer assignaments (wrapper classes shouldn't give such
problems), i've tried your solution, and this one too:

int newBonus = f.getInt(boss);

but i keep on getting the same error at the same line. and finally
yes, my project is simply to learn more about reflection. i know i
could have simply done this via standard set/get methods :)
plus, to allow a pure OO programming, i'd avoid to change the type of
bonus from Integer to int :)
Click to expand...


ty, i found the problem: it was just that getInt() method returns an
int, while my field was an Integer. i should have used

Integer newBonus = (Integer)f.get(boss);

get returns an object, that i just cast to Integer. sometimes i feel
so stupid :x
 

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