Why only final variables can be accessed in an inner class ?
Variables declared in a method need to declared as final if they are to be accessed in an inner class which resides in that method. My question is...
1. Why should i declare them as final ? What's the reason?
2. If i declare them as final, could they be modified in inner class ? since final variables should not modify their value.
(Got an error posting this, so I hope we don't end up with two...)
But what if i want to change the final local variable within that method instead of within anonymous class.You can't. You can't change the value of a final variable.
Should i use same thing like having another local variable as part of method and initializing it with the final local variable?You could do. But as in the first example I posted you are changing the value of the nonfinal variable not the final one. Because final variables can't be changed.
If so, don't you think it is redundant to have so many local variables for so many final local variables just to change them within that method?If you are worried that a variable might be redundant, don't create it. If you must create it to meet some need then it's not redundant.
Or is there any alternate way?Any alternate way to do what?
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Hi,
I am getting the following Axis Fault with content
Exception in thread "main" AxisFault
faultCode: {http://schemas.xmlsoap.org/soap/envelope/}Server.userException
faultSubcode:
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java.lang.IllegalAccessException: Class org.apache.axis.providers.java.JavaProvider can not access a member of class Hello with modifiers ""
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at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:834)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:764)
at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:148)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1242)
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import java.net.URL;
import javax.xml.rpc.ParameterMode;
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import org.apache.axis.client.Service;
import org.apache.axis.encoding.XMLType;
import org.apache.axis.utils.Options;
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public ClientHello(){
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call.setReturnType(XMLType.XSD_STRING);
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System.out.println(result);
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class Hello {
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return "Hello "+ message;
I am not sure why the message is substituted with "" instead of the parameter i have sent in args[1].
Please help me out in this regard.
Thanks,
winkidzzThanks swatdba.
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package org.struts.ets.utility;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.Iterator;
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at sun.reflect.Reflection.ensureMemberAccess(Unknown Source)
at java.lang.reflect.Field.doSecurityCheck(Unknown Source)
at java.lang.reflect.Field.getFieldAccessor(Unknown Source)
at java.lang.reflect.Field.set(Unknown Source)
at org.struts.ets.utility.DynamicObjectCreation.main(DynamicObjectCreation.java:35)
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Class<?> c = FieldTrouble.class; OR
/*Class<?> c = null;
try
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Edited by: ..-__Kris__-.. on Feb 21, 2008 10:26 AM
Edited by: ..-__Kris__-.. on Feb 21, 2008 10:26 AMAny hidden performance or memory issue here?
Let us consider an object:
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private String fieldA;
private String fieldB;
private String fieldC;
private String fieldD;
private String fieldE;
//... say 50 declared fields....
public SomeObject()
public SomeObject(String fieldA, String fieldB)
this.fieldA = fieldA;
this.fieldB = fieldB;
// getters and setters..
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This is where I am unable to figure out if this has anything to do with performance or memory, rather, what is the difference between the many possible ways you can initialize an object when there are too many fields which you probably won't use? Either create a new constructor with only two input arguments OR a generic constructor with all fields as input arguments but all those fields which you won't use assigned NULL's OR create another new object with only two declared fields
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Field[] fields = someObj.getClass().getDeclaredFields();
System.out.println("Number of available fields: " + fields.length);
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}Edited by: ..-__Kris__-.. on Mar 23, 2008 5:04 PM
Edited by: ..-__Kris__-.. on Mar 23, 2008 5:05 PM -
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I'm using the flex SwfLoader to load a flash side
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Using the Slide class (Flash Professional only)
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Can enclosing instance for an inner class be null?
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In this third class I have statements like this:
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The offending statement is actually
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The following code demonstrates this....
class Solution
class SolutionStep
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I wonder if you can help me..
At the company i work in, some application has a problem where the same applicatoin can not be opened if there are already somebody else opening the same application. what is the cause of this behaviour?
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Why Inner class cannot access static variables
Why is it that inner class can use only static final variables of the outerclass, and not ordinary static variables of the outer class. "Yes the JLS sepcifies that only final static variables can be used inside an inner class, esp a non blank final variable". But why this restriction.
Thanks.so what are final static variables treated as if they
are not variables. So if the final static value is
not loaded when the class is loaded how will the
class know about the value.??The actual value wil be substituted for the name of a static final value at compile time. That's why you can use them in switch statements where you can't use any variable variable.
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I am trying to manually make a drawing program similar to this one
http://javafx.com/samples/Draw/
However I am running into issues involving inner classes and finals.
"local variable size is accessed from within inner class; needs to be declared final"
It wants me to make either SIZE or size a final. However once final, I can't change the variable.
I have often used the variable in a for loop to assign a value(though maybe it was a bad practice?) however I am not sure the best way to handle this.
Any suggestions?
Thanks!
int SIZE = 1; //somewhere else
for( int size = 0 ; size < 5 ; size++){
Circle circle = new Circle(D/Padding);
circle.setOnMousePressed(new EventHandler<MouseEvent>(){
public void handle(MouseEvent me){
SIZE = size;
);edit:
I am well aware this isnt neccesarily a javafx specific thing, but more of a general java poor programming knowledge.
I also know that the mouseadapter is an anonymous class and can only access final.
I am just looking for any suggestions on how to best handle this.
Edited by: namrog on Jul 5, 2011 10:51 AM
Edited by: namrog on Jul 5, 2011 10:59 AMnamrog wrote:
I am trying to manually make a drawing program similar to this one
http://javafx.com/samples/Draw/
However I am running into issues involving inner classes and finals.
"local variable size is accessed from within inner class; needs to be declared final"
It wants me to make either SIZE or size a final. However once final, I can't change the variable.Yes, that's the point. If a local variable is to be used by an instance of a nested class, that nested instance can live on long after the local variable goes out of scope. So it needs its own, separate copy of the variable. However, since, as far as we are concerned, there is only one variable, that variable needs to be final, so that there will not be issues with keeping the two copies' values coherent.
I have often used the variable in a for loop to assign a value(though maybe it was a bad practice?) however I am not sure the best way to handle this.
Any suggestions?Create a final variable and copy the value of your non-final variable to it.
int nonFinal =...;
final int theFinalCopy = nonFinal;
new Whatever() {
void doStuff() {
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