Final class: methods/fields automatically final?

As a final class cannot be subclassed, methods/fields cannot be overwritten. But is there a performance/security difference between
public final class A {
    public static final String S = "S";
    public final static do() {}
}and
public final class A {
    public static String S = "S";
    public static do() {}
}?

As a final class cannot be subclassed, methods/fields
cannot be overwritten. But is there a
performance/security difference betweenAll methods of a final class are implicitly final.
Fields are not (you could demonstrate that very easily by altering the value of the field S in your example).

Similar Messages

How to recognize the name of invoked classes&methods&fields in a class

I am now doing some programming used to recognize the name of all classes, methods, constructors and fields invoked from other classes in a given class. This recognition is required automatical. Now I really have no idea how to realize it. Can anyone please give me some suggestions how to programme it?
Now I show you a specific example to make sure you understand my question.
From the following example, firstly I've no idea what outer classes, methods and fields are used in class "PointShadowProtocol". However, the expected functionality of realization is to find out: 1, the name of two used outer classes: Shadow, Point; 2, invoked constructor: Shadow s=new Shadow(int x,int y); 3, invoked methods: Point.getX()， Point.getY()， Point.printPosition()，Shadow.offset，Shadow.printPosition(); and 4, invoked field: Point.x,Point.y,Shadow.x,Shadow.y
public class PointShadowProtocol{
private int shadowCount=0;
public static Shadow getShadow(Point p){
Shadow s=new Shadow(p.x,p.y);
return s;
public void setting(Point p){
Shadow s=new Shadow(p.x,p.y);
shadowCount++;
public void settingX(Point p){
Shadow s=getShadow(p);
s.x=p.getX()+Shadow.offset;
p.printPosition();
s.printPosition();
public void settingY(Point p){
Shadow s=getShadow(p);
s.y=p.getY()+Shadow.offset;
p.printPosition();
s.printPosition();
Actually, after realizing this functionality, I will use these results to automatically generate the related class stub, method stub, field stub, which can be used to test the given class "PointShadowProtocol", probably equivalent to unit test.
Any suggestions are welcome. Thank you in advance for your reply.

Using BCEL sounds a good idea for a class in Java. Actually, I want to target an aspect, which is from AspectJ, without knowing any invoked classes, class methods and fields inside an aspect in the first place (examples of an aspect is as showed below). An aspect in AspectJ is just like a class in Java. But an aspect can't be compiled if the invoked outer classes and methods don't exist. (In fact, the weaving of an aspect into classes happens in the compile time, an aspect can't be compiled if the woven classes (or invoked classes) don't exist, which means I have to find out the all the invoked classes, class methods and fields in that aspect before the compile time) So BCEL could not apply into an aspect in AspectJ.
I am sorry to introduce new concepts here. However,the solution to find out all the invoked outer classes, class methods and fields in a given class before the compile time can be applied to an aspect as well.
Thank you for your time to think about my question.
public aspect PointShadowProtocolAspect {
     private int shadowCount=0;
     public static Shadow getShadow(Point p){
          Shadow s=new Shadow(p.x,p.y);
          return s;
     pointcut setting(Point p): target(p)&&call(Point.new(int,int));
     pointcut settingX(Point p):target(p)&&call(void Point.setX(int));
     pointcut settingY(Point p):target(p)&&call(void Point.setY(int));
     after(Point p): setting(p){
          Shadow s=new Shadow(p.x,p.y);
          shadowCount++;
     after(Point p):settingX(p){
          Shadow s=getShadow(p);
          s.x=p.getX()+Shadow.offset;
          p.printPosition();
          s.printPosition();
     after(Point p):settingY(p){
          Shadow s=getShadow(p);
          s.y=p.getY()+Shadow.offset;
          p.printPosition();
          s.printPosition();

Final class and private constructor

Whats the difference in a final class and a class with private constructot?
If we can make a class non-extendable by just giving private constructor then whats the advantage of final class? (I know final is very useful for many other things but just want to get info in this contaxt)

You can extend a class with a private constructor,I'm not sure about that. The compiler will complain.
KajThat depends on the signature of the private constructor.
If it's the no-arg constructor and you don't declare another constructor which you explicitly call from your derived class you will indeed get an error.
If however you never call it (and there's no way it can implicitly get called) from a derived class there should be no problem.
class Private1 {
     private int q;
     private Private1() {
     public Private1(int i) {
          q = i;
     public void print() {
          System.out.println(q);
public class Public1 extends Private1 {
     public Public1() {
          super(1);
     public static void main(String[] args) {
          new Public1().print();
}for example compiles and runs perfectly.
But remove the call "super(1);" from the constructor and it will fail to compile.

Overidding a method defined in a Final class via an interface.

Hi,
Is it possible to override methods of a final class
which has implemented methods of an interface.
interface A{
     void method1();
public final class FinalityA implements A{
     public void method1(){
          // Code
}Now,I would like to override the functionality of
method1() defined in class FinalityA.
I cannot subclass FinalityA as this class is final.
// Invalid.
class Myclass extends FinalityA{
}Is it possible to override the functionality defined in method1()
Please suggest

You can do:
public class MyClass implements A {
   private final FinalityA _wrapee;
   public MyClass(FinalityA wrapped) {
       _wrapee = wrapped;
public void method1() {
       .. do some special processing
      _wrapee.method1();
       .. do some more stuff
        }If you want to get really clever you can do stuff with java.lang.reflect.Proxy that allows you to automatically pass on calls to interface methods (this kind of thing is increasingly used for stuff like transaction management).
What you can't do is to fiddle with the code of the method if called from a reference to FinalityA rather than a reference to the interface. The whole point of final classes and methods is to prevent that.

Inaccessible with local variable(non-final) via method local inner class

Hi All,
Usually local variables, including automatic final variable live on the stack and objects & instanace variables live on the heap.The contracts for using the method local inner class should allow merely method final variable, not non-final stack variable.
Can anyone please clarify me ,behind the scene what is actual fact why method inner class should not access the stack(method) variable and only allow final variable?
Is anything correlated with the stack and heap aspects?
Thanks,
Stalin.G

[email protected] wrote:
...behind the scene what is actual fact why method inner class should not access the stack(method) variable and only allow final variable?...explained by dcminter and Jardium in [an older thread|http://forums.sun.com/thread.jspa?messageID=10694240#10694240|http://forums.sun.com/thread.jspa?messageID=10694240#10694240]:
...Final variables are copied into inner classes - that's why they have to be declared final; to avoid the developer making an incorrect assumption that the local variable can be modified and have the change reflected in the copy.
When a local class uses a local variable, it doesn't actually use the variable. Instead, it takes a copy of the value which is contained in the variable at the moment the class is instantiated. It's like passing the variable to a constructor of the class, except that you do not actually declare any such constructor in your code.
To avoid messy execution flows to be present in a Java method, the Java language authors thought it was better to allow a single value to be present in such a variable throughout all its life. Thus, the variable has to be declared final.
...HTH

Final method and final class

What is final method and final class in abap objects.

ejp wrote:
Since that doesn't work--or would overyy complex to implement... would be impossible to implement. Once the method-local copy goes out of existence, ipso facto it can never be changed. This is the whole point.I consider it impossible too, but I'm not a language/compiler/runtime expert, so I allowed for the possibility that there could be some way to do it--e.g. local variables that are references in inner classes live on the heap instead of the stack, or something. My point isn't that it's possible, just that if it were somehow to be done, it would by ugly, so we may as well consider it impossible--it just ain't gonna happen.
we go with the logic, "Okay, we need to copies, but keeping them in sync is a nightmareNo, it is +meaningless.+No, it's not meaningless. If we have the two copies, and they're not final, then after the inner object is created, the method can continue running, and either the method or the inner object could modify its copy. As far as our code knows, it's the same variable, so there'd have to be some way to keep them in sync. That's either impossible or undesirably complex--like the above, it doesn't matter which--so it's final in order to get past the issue of keeping the copies in sync.

How do I redefine a Method of a Final Class?

Hi,
Is it possible to redefine a method of a final class and if so, can someone please give me a brief example of that technique?
Thank you very much!
Andy

Hi,
Please find the example.
Program Description :      Interface I1 contains two methods : M1 and M2.
I1 is included and incorporated in class : C1 with M2 as a final method. Both the methods are implemented in class C1.
Class C2 is a subclass of class C1. It redefines method : I1M1 and re-implements it, but it does not do that for I1M2 as that is declared as final method.
In the START-OF-SELECTION block, object OREF1 is created from class C1 and OREF2 from class C2 and both the methods M1 and M2 are called using both the objects.
Example:
report ytest .
interface i1 .
methods : m1 ,
            m2 .
endinterface.
class c1 definition.
public section.
   interfaces : I1 final methods m2 .
endclass.
class c1 implementation.
method i1~m1.
   write:/5 'I am m1 in c1'.
endmethod.
method i1~m2.
   write:/5 'I am m2 in c1'.
endmethod.
endclass.
class c2 definition inheriting from c1.
public section.
   methods : i1~m1 redefinition .
endclass.
class c2 implementation.
method : i1~m1.
   write:/5 'I am m1 in c2'.
endmethod.
endclass.
start-of-selection.
data : oref1 type ref to c1,
         oref2 type ref to c2 .
   create object : oref1 , oref2.
   call method : oref1->i1~m1 , u201C Output : I am m1 in c1
                  oref2->i1~m1 , u201C Output : I am m1 in c2
                  oref1->i1~m2 , u201C Output : I am m2 in c1
                  oref2->i1~m2 . u201C Output : I am m2 in c1
Output :      I am m1 in c1
I am m1 in c2
I am m2 in c1
I am m2 in c1
Thanks,
Anitha

Why we are making a variable as final in method inner class ?

Why we are making the variable as final (method inner class) while we are accessing the method variable in inner class ?
regards,
namanc

As far as I can tell, the only reason is to protect the programmer: when the inner class instance is constructed, it is given the then-current value of the variable. If the variable (or method parameter) later changes, the value held by the inner class would not. By making the variable final, the programmer doesn't have to worry about them staying in sync.
Here's some code to ponder:
public class InnerExample
    void printMe( final int x )
        Runnable runMe = new Runnable()
            public void run()
                System.out.println(x);
        (new Thread(runMe)).start();
}When compiled with the Sun JDK 1.4.2, you get this bytecode:
void printMe(int);
Code:
   0:   new     #2; //class InnerExample$1
   3:   dup
   4:   aload_0
   5:   iload_1
   6:   invokespecial   #3; //Method InnerExample$1."<init>":(LInnerExample;I)V
   9:   astore_2
   10: new     #4; //class Thread
   13: dup
   14: aload_2
   15: invokespecial   #5; //Method java/lang/Thread."<init>":(Ljava/lang/Runnable;)V
   18: invokevirtual   #6; //Method java/lang/Thread.start:()V
   21: returnAt line (byte) 5, it loads the passed value onto the stack; at line 6, it invokes the inner class constructor (which is created by the compiler). Nothing in this sequence of code would prevent use of a non-final variable.

Protected method in Final Class

Hi all
Can we have protected method in Final class ?
If so how is it possible ?
Vicky

Final classes cannot have subclasses and hence no need of protected methods.
No comments on possibility.
Check this link from SAP help to know more :
http://help.sap.com/saphelp_nw70/helpdata/en/dd/4049c40f4611d3b9380000e8353423/content.htm
Hope this helps you.
Edited by: Harsh Bhalla on Dec 19, 2009 3:35 PM

Java.lang.VerifyError: Cannot inherit from final class

Hi i am trying to call a crystal report from jsp but i am getting this error
error:-
org.apache.jasper.JasperException: Cannot inherit from final class
     org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:460)
     org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:355)
     org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
     org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
     javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
root cause
javax.servlet.ServletException: Cannot inherit from final class
     org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:841)
     org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:774)
     org.apache.jsp._1_jsp._jspService(_1_jsp.java:95)
     org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
     javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
     org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:331)
     org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
     org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
     javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
root cause
java.lang.VerifyError: Cannot inherit from final class
     java.lang.ClassLoader.defineClass1(Native Method)
     java.lang.ClassLoader.defineClass(Unknown Source)
     java.security.SecureClassLoader.defineClass(Unknown Source)
     org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:1853)
     org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:875)
     org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1330)
     org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1209)
     java.lang.ClassLoader.loadClassInternal(Unknown Source)
     com.crystaldecisions.reports.sdk.ReportClientDocument.open(Unknown Source)
     org.apache.jsp._1_jsp._jspService(_1_jsp.java:64)
     org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
     javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
     org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:331)
     org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
     org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
     javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
my jsp is
<%@ page import="com.crystaldecisions.report.web.viewer.*" %>
<%@ page import="com.crystaldecisions.sdk.occa.report.data.*" %>
<%@ page import="com.crystaldecisions.reports.sdk.ReportClientDocument" %>
<%
    Object reportSource = session.getAttribute("reportSource");
    if (reportSource == null)
       String report = "report.rpt";
       ReportClientDocument reportClientDoc = new ReportClientDocument();
       reportClientDoc.open( "report.rpt", 0);
       reportSource = reportClientDoc.getReportSource();
       session.setAttribute("reportSource", reportSource);
    CrystalReportViewer viewer = new CrystalReportViewer();
    viewer.setReportSource(reportSource);
       viewer.setEnableLogonPrompt(false);
    viewer.setOwnPage(true);
    viewer.processHttpRequest(request, response, getServletConfig().getServletContext(), null);
%>
and in my WEB-INF/lib i included jar files namely
Concurrent.jar,CrystalCharting.jar,CrystalCommon.jar,CrystalContentModels.jar,CrystalExporters.jar,CrystalExportingBase.jar,CrystalFormulas.jar,CrystalQueryEngine.jar,CrystalReportEngine.jar,CrystalReportingCommon.jar,icu4j.jar,jrcerom.jar,keycodeDecoder.jar,log4j.jar,MetafileRenderer.jar,rasapp.jar,rascore.jar,rpoifs.jar,serialization.jar,URIUtil.jar,xml-apis.jar,xbean.jar,xercesImpl.jar,webreporting.jar,webreporting-jsf.jar
please help me

You can't inherit from a final class.
So - are you trying to inherit from a final class?
Sincerely,
Ted Ueda

Abstract class & final class

Which is more correct... Or which is the more preferred way.
abstract class A
final method1(){}
final method2(){}
final method30(){}
}or
final class A
private A(){}
method1(){}
method2(){}
method3(){}
}My understanding is that both classes cannot be instantiated. The first one requires writing 'final' for EACH method. The second one involves writing a private constructor.

It depends on what you are trying to do. If you are trying to make a class that can be sub-classed but has some methods that cannot be overriden, then "abstract class A" with final methods is the way to go. If you want a class that cannot be sub-classed or instantiated then "final class A" with private constructor is the way to go.
classes cannot be instantiatedOnly true for "final class A" because you made the only constructor private. Not true for the abstract one.// you forgot return values for the methods
abstract class A
final static /*void*/ method1(){} // package private
final static /*void*/ method2(){} // package private
final static /*void*/ method30(){} // package private
// this would work
A a = new A(){};
// if I am in the same package as A, then this would work
a.method1();
// or this
public class B extends A
public B(String whatever)
    // Although, I cannot override the super methods
    // becuase they are all declared as final
    // I can only invoke them if I am in the same package. You
    // declared them as package private instead of class "private"
}Using final as a class modifier disables the ability to sub-class it but does not disable the ability to create an object of that class. You must make a private constructer. If the only constructor is "private" then you can't subclass or instantiate, so making the class final is uneeded.

Final class CL_PT_EMPLOYEE. Why?

Today I tried to make a local class as a sub class to CL_PT_EMPLOYEE and found out that this class was defined as a final class.
Does any one have an idea why the class CL_PT_EMPLOYEE has been defined as a final class. Is that to stop any re-use of SAP code. Any one from SAP?
(P.S. Please dont over exert yourself in explaining the meaning of a final class to me)

Hello Ahsan,
Sorry if I wasn't clear, this is an example of sarcasm. The use of the word "apparently" should have given it away, and particularly the exaggeration "untold harm" was supposed to convey the impression that I do not believe this for one minute.
This is just what I was told by OSS, it was about two years ago and there were several conversations back and forth, some by telephone. Basically, by allowing us to create a subclass we would be able to redefine a superclass method and... well, I am not quite sure what the risk is to be honest, but SAP seemed to think this was a dangerous tool to let loose upon us customers. It was the type of response that is under discussion in this thread:
A (disbelieving) question regarding the OSS
As others have a really suggested, composition is the answer and usually a better technique.
The only time when you should need to create a subtype of a standard SAP class is if you have to use polymorphism to feed your own version of an SAP class to something else that expects a particular class as input. This is the <sarcasm>"risky" part by which we could damage the system according to OSS</sarcasm>, yet is quite commonly used in workflow. In the BOR world they even provided a neat feature called delegation (basically a reverse inheritance) to accomplish this.
Cheers,
Mike
Edited by: Mike Pokraka on Sep 2, 2008 5:59 PM - clarification

Clientgen Exception - java.lang.VerifyError:Cannot inherit from final class

When i create a client jar from webservice ear the ant taks fails with compiler errors, such as:
CreateProxy:
[clientgen] Generating client jar for earname.ear(WebServiceName_WS) ...
BUILD FAILED
java.lang.VerifyError: Cannot inherit from final class
at java.lang.ClassLoader.defineClass0(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:539)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:123)
at weblogic.utils.classloaders.GenericClassLoader.findLocalClass(GenericClassLoader.java:480)
at weblogic.utils.classloaders.GenericClassLoader.findClass(GenericClassLoader.java:182)
at java.lang.ClassLoader.loadClass(ClassLoader.java:289)
at java.lang.ClassLoader.loadClass(ClassLoader.java:235)
at weblogic.utils.classloaders.GenericClassLoader.loadClass(GenericClassLoader.java:224)
at weblogic.webservice.server.WebServiceFactory.loadNonArrayClass(WebServiceFactory.java:1318)
at weblogic.webservice.server.WebServiceFactory.loadClass(WebServiceFactory.java:1293)
at weblogic.webservice.server.WebServiceFactory.initTypeMaps(WebServiceFactory.java:384)
at weblogic.webservice.server.WebServiceFactory.createFromMBean(WebServiceFactory.java:184)
at weblogic.webservice.tools.build.internal.WSDLGenImpl.getWebServiceRuntime(WSDLGenImpl.java:240)
at weblogic.webservice.tools.build.internal.WSDLGenImpl.run(WSDLGenImpl.java:135)
at weblogic.webservice.tools.build.internal.ClientGenImpl.doClientGenFromEAR(ClientGenImpl.java:438)
at weblogic.webservice.tools.build.internal.ClientGenImpl.run(ClientGenImpl.java:345)
at weblogic.ant.taskdefs.webservices.clientgen.ClientGenTask.doClientGen(ClientGenTask.java:351)
at weblogic.ant.taskdefs.webservices.clientgen.ClientGenTask.execute(ClientGenTask.java:208)
at org.apache.tools.ant.Task.perform(Task.java:341)
at org.apache.tools.ant.Target.execute(Target.java:309)
at org.apache.tools.ant.Target.performTasks(Target.java:336)
at org.apache.tools.ant.Project.executeTarget(Project.java:1339)
at org.apache.tools.ant.Project.executeTargets(Project.java:1255)
at org.apache.tools.ant.Main.runBuild(Main.java:609)
at org.apache.tools.ant.Main.start(Main.java:196)
at org.apache.tools.ant.Main.main(Main.java:235)
Total time: 25 seconds
This is a ant command:
<clientgen ear="${build}/earname.ear" onlyConvenienceMethod="true" warName="webservice.war" serviceName="WebServiceName_WS" packageName="my.package.webservices.generated" autotype="true" clientJar="${build.dist}/client/WebServiceName_WS.jar" overwrite="false" useServerTypes="true" keepGenerated="false" generateAsyncMethods="false" saveWsdl="true" j2me="false" useLowerCaseMethodNames="true" typePackageName="my.package.webservices.generated" usePortNameAsMethodName="false" />
My webservice do not include any final class.
I'm using WebLogic 8.1 SP4.Is there a solution for above problem?
Thanks.
Regards.

Hi all,
I m also facing quite similar problem.
I have one sample JMX program, which i want to collect data from weblogic 9.2.
but when i compile sample program on jdk 1.4 and run it on JDK 1.4 it throws following exception
java.lang.VerifyError: class weblogic.utils.classloaders.GenericCl
assLoader overrides final method .
ERROR 02/13 09:54:03 Stderr 700100 at java.lang.ClassLoader.defineClass0(Native Method)
ERROR 02/13 09:54:03 Stderr 700100 at java.lang.ClassLoader.defineClass(Unknown Source)
ERROR 02/13 09:54:03 Stderr 700100 at java.security.SecureClassLoader.defineClass(Unknown Source)
ERROR 02/13 09:54:03 Stderr 700100 at java.net.URLClassLoader.defineClass(Unknown Source)
ERROR 02/13 09:54:03 Stderr 700100 at java.net.URLClassLoader.access$100(Unknown Source)
ERROR 02/13 09:54:03 Stderr 700100 at java.net.URLClassLoader$1.run(Unknown Source)
ERROR 02/13 09:54:03 Stderr 700100 at java.security.AccessController.doPrivileged(Native Method)
ERROR 02/13 09:54:03 Stderr 700100 at java.net.URLClassLoader.findClass(Unknown Source)
ERROR 02/13 09:54:03 Stderr 700100 at java.lang.ClassLoader.loadClass(Unknown Source)
ERROR 02/13 09:54:03 Stderr 700100 at java.lang.ClassLoader.loadClass(Unknown Source)
but sample program works fine if i run it on JDK 1.5..
can someone tell me...wats reason?
Thanks
Nihil

Question about Abstract,Final Class

when we are using final keyword along with class definition .we are making that class final, means we can’t extend that class. The same thing happens when we make our constructors private. From usability perspective both are same ? or is there any difference?
Secondly accounting to java syntax a class can be either final or abstract and not both .Then why language specification doesn't impose any restriction on making abstract classes constructor private. We can create an Abstract class with private Constructor (Basically utility class with all methods are static) ,to make this class Singleton .This situation is equal to abstract final class ?
Thanks,
Paul.

EJP wrote:
when we are using final keyword along with class definition .we are making that class final, means we can’t extend that class. The same thing happens when we make our constructors private.No it doesn't.
Secondly accounting to java syntax a class can be either final or abstract and not both.Correct.
Then why language specification doesn't impose any restriction on making abstract classes constructor private.Why should it? That proposition doesn't follow from your previous sentence.I think OP is asking about this case
public abstract class WTF {
private WTF() {}
private WTF(...) {}
}where the class is abstract and all the c'tors are final. It's an abstract class that cannot be extended, much like a final abstract class would be if it were allowed. So, since purpose of abstract classes is to be extended, the OP seems to be asking, "Why can we, in this fashion, create an abstract class that cannot be extended?"
I don't know the answer to that, but I would guess that, while final is an explicit syntactical element for the purpose of making a class non-extensible, in the all-private-c'tors case, the non-extensibility is simply a side effect, and probably enough of a corner case that it wasn't worth the effort to explicitly forbid it in the spec.
I also think it's something not worth thinking much about. It was certainly not a key point of some grand design.

TextLayout not Serializable AND final class - can't extend and save objects

As the title reads, I am using a TextLayout object in a class called Foo.
I want to be able to serialize Foo and save it to the HD. This can't be done because TextLayout does not implement Serializable.
So I tried to create a new class that extended the TextLayout class. This wasn't possible because TextLayout is defined as:
public final class TextLayout
extends Object
implements Cloneable
Basically, I have no clue how to be able to save my Foo class to the HD since I can't serialize the TextLayout object inside the Foo class. I would really appreciate help, because it is quite important that this works.
Thanks.

Siniz wrote:
I have never dabbled with with transient variables, but I just read up on it and understand what you are getting at. Is this really the only way?
The reason why I need to use TextLayout is because I need the bounding box of the text. I see no other way to get a bounding box around text than using TextLayout.That's a question for the swing/awt forums.
I am also not entirely sure what you mean when you say I should write my own writeObject and readObject methods? You are saying I should entirely ditch the ObjectOutputStream methods?No, you implement those methods on your class in order to customize serialization. Please see the javadocs on the Serializable interface.

Final class: methods/fields automatically final?

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