Illegal combination of modifiers: abstract and synchronized

Hello all:
I have an error from my java compiler and need some help to know the underlying reason
why this statement is wrong.
the following statement is defined in an abstract class.
public abstract synchronized boolean isLeaf();when I try to compile it, i got the following error.
illegal combination of modifiers: abstract and synchronized
so i know this statement is not valid.
does anyone tell me why?
thank you
-Daneil

synchronization of a method is not inherited. the synchronized keyword, when applied to a method realy is a short-cut to put this about the method body:
//instance method:
synchronized(this)
//static method
synchronized(Blah.class)
}It only applies to the currently declared method. There is no way to require that an implementation of tyour method is synchronized.

Similar Messages

Sqlloader -350 illegal combination of non alphanumeric character

hi all,
i'm using owb 10.2.0.1
i have a file in my D:\2122008.txt and a table in oracle DB
created a map from file to table.....
generated a code and saved in D:\orahome_1\owb\codegen\ctl\Employee.ctl
deployed in target database...
when is start from OWB i get the following error
RPE-01013: SQL Loader reported error condition, number 1.
SQL*Loader: Release 10.2.0.1.0 - Production on Thu Mar 6 17:50:01 2008
Copyright (c) 1982, 2005, Oracle. All rights reserved.
SQL*Loader-500: Unable to open file (d:\EMPLOYEE.ctl)
SQL*Loader-553: file not found
SQL*Loader-509: System error: The system cannot find the file specified.
so i planned to run by invoking sql*loader..
this is the generated code
OPTIONS (BINDSIZE=50000,ERRORS=50,ROWS=200,DIRECT=TRUE,READSIZE=65536,FILE='F_21022008_TXT')
CONTINUE_LOAD DATA
CHARACTERSET WE8MSWIN1252
INFILE '{{FILE_EMP_LOCATION1.RootPath}}{{}}21022008_TXT'
DISCARDMAX 0
CONCATENATE 1
INTO TABLE "DMT_ADMIN"."AZBJ_ONEEMPLOYEE_DATABASE"@"dwhtest"
APPEND
REENABLE DISABLED_CONSTRAINTS
FIELDS TERMINATED BY X'09' OPTIONALLY ENCLOSED BY 'X' SKIP 0
"REC_SRNO" POSITION(1) INTEGER EXTERNAL ,
"EMPLOYEENUMBER" INTEGER EXTERNAL ,
"EMPLOYEENAME" CHAR ,
"EMPDOB" CHAR ,
"GENDER" CHAR ,
"DEPARTMENT" CHAR ,
"DESIGNATION" CHAR ,
"OPUSCODE" CHAR ,
"BRANCHCODE" CHAR ,
"OFFICEMAIL" CHAR ,
when i execute in sqlldr it is openeing the ctl file but gives the following error
sql*loader-350: syntax error at line 21
illegal combination of non-alphanumeric characters
INTO TABLE "DMT_ADMIN"."AZBJ_ONEEMPLOYEE_DATABASE"@"dwhtest"
the error is comming at the symbal "@"
tried out several ways but could'nt resolve the prob
anyone out there to help me....

shld i need to keep the source files where OWB server is installed or can i run the process by keeping the files in my client systems local directory?

SQL*Loader-350: Illegal combination of non-alphanumeric characters

Hi all,
how to skip a column in control file.
i.e.
I have a table with 10 columns and FAT file contains 11 columns.
how to skip a last column ?
and
I added extra column to Table and I changed the control file too.
but i am getting error.
SQL*Loader-350: Syntax error at line 115.
Illegal combination of non-alphanumeric characters
thanks in Advance.

Tom Kyte has an elaborate solution on his page:
http://osi.oracle.com/~tkyte/SkipCols/index.html
Or post the table description and the control file, so we can have a look at it.

Illegal combination when importing xml file into xmltype column

I have the following control file.
LOAD DATA
CHARACTERSET UTF8
INFILE *
INTO TABLE IMPORTRAWXML TRUNCATE
SITEID constant 0
,VENDORID constant 17
,SITEFORMATID constant 2
,"\\plutonium\outcomes\AHA GWTG-Outpatient\Programs\DataTransfer\LoadTest\V17_standard_test.xml" filler char(1000)
,RAWDATA LOBFILE ("\\plutonium\outcomes\AHA GWTG-Outpatient\Programs\DataTransfer\LoadTest\V17_standard_test.xml")
TERMINATED BY EOF
)When I run it using sqlldr command line I get the following error:
SQL*Loader-350: Syntax error at line 1.
Illegal combination of non-alphanumeric characters
<?xml version="1.0" encoding="ISO-8859-1"?>Does anyone have any idea what I am doing wrong here? If I remove the fully resolved path (both the control file and xml file are in the same folder) it tells me it can't find the file to load.
HELP!!!!
Thanks,
Eva

evaleah wrote:
I have made sure all my home settings are correct in my registry editor and they are. Another thing to note is the control file I am using works 100% perfectly, beautifully when called from Toad for Oracle. It is when called from the command line utility that it fails. Is there anyway to determine what the difference could be?
So we know that I can work (toad works), but it doesn't yet work in a "cmd" environment.
Just as any other program Toad is also a client and uses NLS and other environment settings. Maybe these are stored in the registry, maybe the are being set by Toad by reading a configuration file while it is started or while running.
As said, on Windows its tricky...
Setting properties in the registry will not mean that they are the same a "cmd" window or maybe not even been set.
If you execute / run "cmd" then the "set" statement/command will output the environment settings that will be used during the livetime of that "cmd" session.
C:/> setIn my laptop environment (windows 7 64 bit) it will show the following
C:\>set
ALLUSERSPROFILE=C:\ProgramData
APPDATA=C:\Users\marco\AppData\Roaming
CommonProgramFiles=C:\Program Files\Common Files
CommonProgramFiles(x86)=C:\Program Files (x86)\Common Files
CommonProgramW6432=C:\Program Files\Common Files
COMPUTERNAME=00-00-000
ComSpec=C:\Windows\system32\cmd.exe
DEFLOGDIR=C:\ProgramData\McAfee\DesktopProtection
FP_NO_HOST_CHECK=NO
HOMEDRIVE=C:
HOMEPATH=\Users\marco
LOCALAPPDATA=C:\Users\marco\AppData\Local
LOGONSERVER=\\AMISNT
MpConfig_ProductAppDataPath=C:\ProgramData\Microsoft\Windows Defender
MpConfig_ProductCodeName=AntiSpyware
MpConfig_ProductPath=C:\Program Files\Windows Defender
MpConfig_ProductUserAppDataPath=C:\Users\marco\AppData\Local\Microsoft\Windows
Defender
MpConfig_ReportingGUID=CA08B82B-EF0A-4107-89D8-ED5BB37E7515
NUMBER_OF_PROCESSORS=2
OS=Windows_NT
Path=C:\oracle\product\11.2.0\dbhome_1\bin;C:\Windows\system32;C:\Windows;C:\Win
dows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\
PATHEXT=.COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC
PERL5LIB=c:\oracle\product\10.2.0\db_1\perl\5.8.3\lib\MSWin32-x64;c:\oracle\prod
uct\10.2.0\db_1\perl\5.8.3\lib;c:\oracle\product\10.2.0\db_1\perl\site\5.8.3;c:\
oracle\product\10.2.0\db_1\perl\site\5.8.3\lib;c:\oracle\product\10.2.0\db_1\sys
man\admin\scripts;
PROCESSOR_ARCHITECTURE=AMD64
PROCESSOR_IDENTIFIER=Intel64 Family 6 Model 23 Stepping 10, GenuineIntel
PROCESSOR_LEVEL=6
PROCESSOR_REVISION=170a
ProgramData=C:\ProgramData
ProgramFiles=C:\Program Files
ProgramFiles(x86)=C:\Program Files (x86)
ProgramW6432=C:\Program Files
PROMPT=$P$G
PSModulePath=C:\Windows\system32\WindowsPowerShell\v1.0\Modules\
PUBLIC=C:\Users\Public
SESSIONNAME=Console
SystemDrive=C:
SystemRoot=C:\Windows
TEMP=C:\Users\marco\AppData\Local\Temp
TMP=C:\Users\marco\AppData\Local\Temp
USERDNSDOMAIN=AMIS
USERDOMAIN=AMIS
USERNAME=marco
USERPROFILE=C:\Users\marco
VBOX_INSTALL_PATH=C:\Program Files\Sun\VirtualBox\
VSEDEFLOGDIR=C:\ProgramData\McAfee\DesktopProtection
windir=C:\Windows
C:\>The only thing that identifies that I have Oracle installed is set in the %PATH% variable and %PERL5LIB%. From the path setting you can also deduct that I have Oracle 11 and Oracle 10 software installed. So when I execute "sqlldr" what NLS settings will it use and which tnsnames.ora alias for example to connect to the database...?
You can you do it and see what happens...
C:\>sqlldr
SQL*Loader: Release 11.2.0.1.0 - Production on Wed May 12 20:36:25 2010
Copyright (c) 1982, 2009, Oracle and/or its affiliates. All rights reserved.
Usage: SQLLDR keyword=value [,keyword=value,...]
Valid Keywords:
...So it will pick the first "sqlldr" in the %PATH% environment setting. But what about NLS...? As said to be absolute sure you will have to set it in your environment.
C:/> set ORACLE_HOME="C:\oracle\product\10.2.0\db_1"
C:\> set
Path=C:\oracle\product\11.2.0\dbhome_1\bin;C:\Windows\system32;C:\Windows;C:\Win
dows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\
PATHEXT=.COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC
PERL5LIB=c:\oracle\product\10.2.0\db_1\perl\5.8.3\lib\MSWin32-x64;c:\oracle\prod
uct\10.2.0\db_1\perl\5.8.3\lib;c:\oracle\product\10.2.0\db_1\perl\site\5.8.3;c:\
oracle\product\10.2.0\db_1\perl\site\5.8.3\lib;c:\oracle\product\10.2.0\db_1\sys
man\admin\scripts;
ORACLE_HOME="C:\oracle\product\10.2.0\db_1"
C:\> echo %ORACLE_HOME%
"C:\oracle\product\10.2.0\db_1"Because if I enter "sqlldr" it will pick the executable from the 11.2 install, but the ORACLE_HOME is set to the wrong environment
Executing sqlldr now will give me an error
C:\>sqlldr
Message 2100 not found; No message file for product=RDBMS, facility=ULMessage 21
00 not found; No message file for product=RDBMS, facility=UL
C:\>Another thing you can notice now is that from that output alone, you can't deduct the Oracle "sqlldr" version anymore. Setting the ORACLE_HOME environment to either 10.2 or 11.2 will cause "sqlldr" to execute normally (at least thats how it looks) BUT in the case of the oracle 10.2 setting it will use the wrong message files etc. At least not the correct software versions / files "sqlldr" is shipped with. So you can (and most of the time) will get strange errors.
C:\> set ORACLE_HOME=C:\oracle\product\10.2.0\db_1
C:\>sqlldr
SQL*Loader: Release 11.2.0.1.0 - Production on Wed May 12 20:45:00 2010
C:\>set ORACLE_HOME=C:\oracle\product\11.2.0\dbhome_1
C:\>sqlldr
SQL*Loader: Release 11.2.0.1.0 - Production on Wed May 12 20:49:50 2010
Copyright (c) 1982, 2009, Oracle and/or its affiliates. All rights reserved.
Usage: SQLLDR keyword=value [,keyword=value,...]
...In the registry you can find a lot of those variables are set for ORACLE_HOME, ORACLE_BASE, SQLPATH, maybe TNS_ADMIN, ORACLE_SID, NLS_LANG. You can find the variables IN the registry on two places. The most common one is the SYSTEM wide environment settings under //HKEY_LOCAL_MACHINE/SOFTWARE/ORACLE and in my case for 11.2 under //HKEY_LOCAL_MACHINE/SOFTWARE/ORACLE/KEY_OraDb11g_Home1.
You could overrule this for to be active on "my user session", my login session as account "marco" under //HKEY_CURRENT_USER/Software/Oracle, but no one using Windows is doing this.
Besides the "cmd" and registry environment, there is a different place as well were you can set these parameters. In windows go to "start", click "control panel", click "system", click tab "Advanced" and then click on the button on the bottum with "Environment Variables". Here you can see the distinction between user and system wide variables as well. Here you can also set NLS_LANG, ORACLE_HOME etc. If I am not mistaken than these will be the default values used in a fresh "cmd" window session. But they can and will interfere with programs you start via clicking them. For example something a Java program like SQL Developer (and/or Toad). If those values are not overrulled by the program by for example using his own variables from a config file or else, those sessings from the "system" / control panel item will be used. If it is the wrong mix, you will encounter strange issues.
Setting ORACLE_HOME and ORACLE_BASE will be used by a lot of derived other settings for example the default place SQL*Net drivers and tnsnames aliases etc will be checked. For example setting the ORACLE_HOME to
C:\> set ORACLE_HOME=C:\oracle\product\10.2.0\db_1will result in that the tnsnames aliases from
C:\> set ORACLE_HOME=C:\oracle\product\10.2.0\db_1\NETWORK\adminwill be used and NOT the ones maybe needed from
C:\oracle\product\11.2.0\dbhome_1\NETWORK\adminYou can overrule this behavior by setting the TNS_ADMIN variable. By default, most explicit form for example on linux and Unix, the following rule will be used by Oracle
1) .tnsnames.ora in the home directory of the user
2) standard default: $ORACLE_HOME/network/admin
3) behavior can be overruled via setting $TNS_ADMINThe fact that you are able via Toad to execute it correctly proves you that it can be done. But Toad uses in your session "SQL*Net" or JDBC or ODBC or ADO or ? via its own configuration environment settings that are being set on which values...?
Both Oracle and Toad use the OSI model (http://en.wikipedia.org/wiki/OSI_model), both have to follow the same rules. There hasn't been changed that much over the years, character set conversions are done in the "two task common" layer of the data transport on either side (client/server) when data travels between a client and server. And don't forget a database can be also be a client when for instance database links are being used. One of the reasons to read old manuals because there the basics are still perfectly explained: http://download.oracle.com/docs/cd/A57673_01/DOC/net/doc/NWUS233/ch2.htm#twotask (Oracle 7.3.4 Networking Manual).
This long long story is just to show you that you have more control if you set variables explicitly in a "cmd" window (and or in a linux/unix shell (as long as the session isn't "forked")) BUT you will have to be precise. Check the environment a set those environment variables that control / that are being used by "sqlldr" (and that are probably more then you realised, for example that SQL_PATH variable is the default directory where SQL*Plus is looking and saving its "SQL" and spool "LIS" files).
HTH

What are the all posible combinations of modifiers

hi
any one know what are the posible combinations of modifiers use with methodsexample
public static aaa(){}//is correct
public private aa(){}//is wrong
i want to know what are the all posible combinations of modifiers use with methods
can any one help me on this problem
thanks
ishkmi
Message was edited by:
ishkmi

i search the web couldnt find can any one help...Really?Yes he did. I'm positive.
>
Which web did you search?The one up near the roof with the Big Hairy Spider in it.
Do you know how to search the web?You stare at it and maintain a count of the bugs that hit it, and the ones that go around, right?
8-)

Difference between modify , append and update

Hi,
 Give me diffference between modify , append and update?
 If possible give me with example.
Thanks & regards
venkravi

Hi,
Syntax Diagram
MODIFY itab
Syntax
MODIFY { itab_line | itab_lines }.
Effect
This statement changes the content of one or several itab_line or itab_lines lines that can be specified using the table key or the table index.
System fields
sy-subrc Meaning
0 At least one line was changed.
4 No lines were changed, since no suitable line was found for the insertion using the table key, or the specified index was greater than the current number of lines for the insertion using the table index.
Note
Apart from using the MODIFY statement, the content of an individual table line can be changed using assignments to field symbols and dereferenced data references that point to the table line.
Exceptions
Non-Catchable Exceptions
Cause: Illegal dynamic specification of a line component
Runtime Error: ITAB_ILLEGAL_COMPONENT
Cause: Illegal key component in the TRANSPORTING list.
Runtime Error: ITAB_ILLEGAL_TRANSP_COMP
Syntax Diagram
APPEND
Syntax
APPEND line_spec TO itab [SORTED BY comp] [result].
Addition:
... SORTED BY comp
Effect
This statement appends one or more rows line_spec to an internal index table itab. If itab is a standard table, you can use SORTED BY to sort the table in a specified way. Use result when appending a single row as of release 6.10 to set a reference to the appended row in the form of a field symbol or a data reference.
For the individual table types, appending is done as follows:
To standard tables, rows are appended directly and without checking the content of the internal table.
To sorted tables, rows are appended only if they correspond to the sort sequence and do not create duplicate entries with unique table key. Otherwise, an untreatable exception is triggered.
To hashed tables, no rows can be appended.
The APPEND statement sets sy-tabix to the table index of the last appended row.
Addition
... SORTED BY comp
Effect
This addition is allowed only if you specify a workarea wa and if you use a standard table, where wa must be compatible to the row type of the table. You can specify component comp as shown in section Specifying Components, however, you can access only one single component and no attributes of classes using the object component selector.
The statement is executed in two steps:
Starting at the last row, the table is searched for a row, in which the value of component comp is greater than or equal to the value of component comp of wa. If such a row exists, the workarea wa is included after this row. If no such row exists, the workarea wa is included before the first row. The table index of all rows following the included rows increases by one.
If the number of rows before the statement is executed is greater than or equal to the number specified in the definition of the internal table in the INITIAL SIZE addition, the newly-created last row is deleted.
Note
When using only the statement APPEND with addition SORTED BY to fill an internal table, this rule results in an internal table that contains no more than the number of rows specified in its definition after INITIAL SIZE and that is sorted in descending order by component comp (ranking).
The SORT statement should usually be used instead of APPEND SORTED BY.
Example
Creating a ranking of the three flights of a connection showing the most free seats.
PARAMETERS: p_carrid TYPE sflight-carrid,
 p_connid TYPE sflight-connid.
DATA: BEGIN OF seats,
 fldate TYPE sflight-fldate,
 seatsocc TYPE sflight-seatsocc,
 seatsmax TYPE sflight-seatsmax,
 seatsfree TYPE sflight-seatsocc,
 END OF seats.
DATA seats_tab LIKE STANDARD TABLE OF seats
 INITIAL SIZE 3.
SELECT fldate seatsocc seatsmax
 FROM sflight
 INTO seats
 WHERE carrid = p_carrid AND
 connid = p_connid.
seats-seatsfree = seats-seatsmax - seats-seatsocc.
APPEND seats TO seats_tab SORTED BY seatsfree.
ENDSELECT.
Exceptions
Non-Catchable Exceptions
Cause: Including a row with identical key (target table defined with UNIQUE)
Runtime Error: ITAB_DUPLICATE_KEY_IDX_OP
Cause: Violation of the sorting sequence due to an APPEND to a sorted table
Runtime Error: ITAB_ILLEGAL_SORT_ORDER:
Cause: Unallowed index value (<= 0) for a FROM, TO, or INDEX specification
Runtime Error: TABLE_INVALID_INDEX
Syntax Diagram
UPDATE dbtab
Syntax
UPDATE target source.
Effect:
The statement UPDATE changes the content of one or more lines of the database table specified in target. The entries in source determine which columns of which lines are changed, and how they are changed.
System fields
The statement UPDATE sets the values of the system fields sy-subrc and sy-dbcnt.
sy-subrc Meaning
0 At least one line has been changed.
4 At least one line was not able to be changed, either because no appropriate line was found, or because the change would generate a line that leads to double entries in the primary key or a unique secondary index in the database table.
The statement UPDATE sets sy-dbcnt to the number of changed lines.
Note
The changes are definitively copied to the database with the next database commit. Until that point, they can still be undone using a database rollback
The statement UPDATE sets a database lock up to the next database commit or rollback, which may lead to a deadlock if used incorrectly.
For the specific database, the number of rows that can be changed within a database LUW in the database table is restricted by the fact that a database system can only manage a certain amount of data in the rollback area and from locks.

Abstraction and Encapsulation i.e basic oops concepts gist and their unders

I have gone to many sites and everywhere got some difference in defintion of abstraction and encapsulation.
Below i tried to summarize the findings of both and have some questions which are inline with understanding.
Encapsulation:-
Hiding internal state and requiring all interaction to be performed through an object's methods is known
as data encapsulation — a fundamental principle of object-oriented programming.
Encapsulation is the technique of making the fields in a class private and providing access to the fields via public methods. If a field is declared private, it cannot be accessed by anyone outside the class, thereby hiding the fields within the class. For this reason, encapsulation is also referred to as data hiding.
Question1:- Agreed that we are hiding the instance variable details but again we do expose them with getter and setter
methods. Is it not the violation of encapsulation? What advantage it provides exposing the internal state thru methods
(like getter and setter) but not declaring stae with public modifier.?
Question2:- If class does not have any state variable and has some just simple methods printing hello world.
Can we still say it is encapsulation?
Abstraction:-Abstraction in Java allows the user to hide non-essential details relevant to user.
Question1:- so we can say Encapsulation is also a feature of abstraction because in ecapsulation also we hide data(state) of object. Right?
Question2:-Say a class has 10 methods . Out of these 10 , only two are exposed for outside world with public modifier.Can we say this is the example of abstraction?
Question3:- Can we say interface/abstract class are the baset examples of abstraction as they just expose the masic details i.e signature of method to outside world?

JavaFunda wrote:
Hi jverd whats your take on original post?Question1:- Agreed that we are hiding the instance variable details but again we do expose them with getter and setter
methods. Is it not the violation of encapsulation? What advantage it provides exposing the internal state thru methods
(like getter and setter) but not declaring stae with public modifier.?
>
I don't think you can say whether an individual get/set "violates encapsulation" without more context. If you're just blindly providing direct get/set for every member variable, then it's likely you don't understand encapsulation. There's still some encapsulation there, however, because the caller can't directly see or modify the state.
Sure, a programmer familiar with coding conventions and possessing some common sense could infer that those get/set methods correspond directly to member variables of the same names, but so what? He still has to go through the methods to see or modify the state, and there could be other stuff going on there. The fact that going through the method makes it a black box to him is why I say there's some level of encapsulation. There's a continuum of how "direct" the access to the internal state is, and I don't think there's a clear delineation between "encapsulated" and "not encapsulated."
For example:
As direct as can be: setX() is simply this.x = x and getX() is simply return x.
Somewhat less direct: getFullName() returns firstname + " " + lastName. There's no member variable called "fullName", and the result is composed by operating on multiple pieces of the object's state.
Still less direct: ArrayList's toString() is "[", followed by the results of each of its elements' toString() methods, separated by commas, followed by "]"
Very indirect: Map.put(). We know that it modifies the state of the Map by adding the key/value pair we specify, and we can infer some things about how it's implemented based on the type of Map. But that abstraction is so far separated from the specific state that represents it, that we would probably say that there's a high level of encapsulation there.
And of course there are other scenarios in between these, and further toward the "encapsulated" end of the spectrum than the Map example. Where do you draw the line between "not encapsulated" and "encapsulated"?
I think a reasonable criterion to use is whether the exposed stated has been exposed because it's a natural part of the behavior of the class.
For instance, Colleciton.size(). It makes sense that as part of a Colleciton's behavior, you'd want it to be able to tell you how many items it holds. In an ArrayList, you would probably have a size variable that gets updated each time an element is added or removed. However, in a ConcurrentSkipListSet, there is no size variable. You have to traverse the Set and count the elements. So is size encapsulated here? Is it in one but not the other? Why? I would say it is in both cases, because part of the natural behavior of a Collection is to tell us its size, so the fact that in some collections that can be done simply be returning the value of a member variable doesn't "violate" encapsulation.
But, after having said all that, my real answer is: I don't care. The answer to "Do get/set violate encapsulation?" doesn't matter to me in the least in how I write my code.
>
Question2:- If class does not have any state variable and has some just simple methods printing hello world.
Can we still say it is encapsulation?
>
I would say no, since there's no state to be encapsulated. However, I supposed one could say that the behavior is encapsulated. It could be implemented any number of different ways, some of which would involve state and some wouldn't, and all we'd see is the public interface and the behavior it provides. I don't know that anybody actual does view it that way though.
And, again, this sort of nitpickery is not actually relevant to anything, IMHO.
>
Question1:- so we can say Encapsulation is also a feature of abstraction because in ecapsulation also we hide data(state) of object. Right?
>
More silly semantics. I wouldn't say that encapsulation is a "feature" of abstraction. I think the two often work together, and there's some overlap in their definitions, or at least in how they're realized in code. (Which can be seen in my long-winded answer to the first quetsion.)
>
Question2:-Say a class has 10 methods . Out of these 10 , only two are exposed for outside world with public modifier.Can we say this is the example of abstraction?
>
Don't know, don't care.
>
Question3:- Can we say interface/abstract class are the baset examples of abstraction as they just expose the masic details i.e signature of method to outside world?
>
No idea what you're saying here, but I expect my answer will again be: "don't know, don't care".
Edited by: jverd on Aug 3, 2011 10:22 AM
Edited by: jverd on Aug 3, 2011 10:22 AM

What is difference between abstraction and encapsulation ?

Hi,
I am trying to figure out the difference between abstraction and encapsulation but confused.
Both are used for data hiding then what is the exact difference ?
Thanks.

Tushar-Patel wrote:
I am trying to figure out the difference between abstraction and encapsulation but confused.
Both are used for data hiding then what is the exact difference ?This is the picture I have:
When you encapsulate something you get an inside and an outside. The outside is the abstraction. It describes how the encapsulated entity behaves viewed from the outside. This is also called the type. Hidden inside is the implementation. It holds detail information about how the type's behaviour is accomplished.
It's a very simplified picture but I think it's quite accurate and it works for me.

Is not abstract and does not override abstract method actionPerformed

I dont how to corr. Please help!! and thank you very much!!
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class test extends JFrame implements ActionListener, ItemListener
          private CenterPanel centerPanel;
          private QuestionPanel questionPanel;
          private ButtonPanel buttonPanel;
          private ResponsePanel responsePanel;
          private JButton b1,b2,b3,b4,b5;               //Create five references to Jbutton instances
     private JTextField t1,t2,t3,t4,t5;          //Create five references to JTextField instances
          private JLabel label1;                    //Create one references to JLabel instances
          private JRadioButton q1,q2,q3;               //Create three references to JRadioButton instances
          private ButtonGroup radioGroup;               //Create one references to Button Group instances
          private int que1[] = new int[5];           //Create int[4] Array
          private int que2[] = new int[5];
          private int que3[] = new int[5];
          private String temp1, temp2, temp3, temp4, temp5, temp6, temp7, temp8, temp9, temp10,
                    temp11, temp12, temp13, temp14, temp15;
public test (String header)
          super(header);
          Container container = getContentPane();
          label1 = new JLabel ("PLease click on your response to ");
          q1 = new JRadioButton("I understand most of the content of this subject",true);
          add(q1);
          q2 = new JRadioButton("I see the relevance of the subject to my degree",false);
          add(q2);
          q3 = new JRadioButton("The workload in this subject is appropriate",false);
          add(q3);
          radioGroup = new ButtonGroup();               //JRadioButton belong to ButtonGroup
          radioGroup.add(q1);
          radioGroup.add(q2);
          radioGroup.add(q3);
          JPanel buttonPanel = new JPanel();
          JPanel responsePanel = new JPanel();
          JPanel questionPanel = new JPanel();
          JPanel centerPanel = new JPanel();
          b1 = new JButton ("Strongly DISAGREE");          //Instantiate JButton with text
          b1.addActionListener (this);               //Register JButtons to receive events
          b2 = new JButton ("DISAGREE");
          b2.addActionListener (this);
          b3 = new JButton ("Neither AGREE or DISAGREE");
          b3.addActionListener (this);
          b4 = new JButton ("AGREE");
          b4.addActionListener (this);
          b5 = new JButton ("Strongly AGREE");
          b5.addActionListener (this);
          buttonPanel.setLayout(new GridLayout(5,1));
          buttonPanel.add(b1);
          buttonPanel.add(b2);
          buttonPanel.add(b3);
          buttonPanel.add(b4);
          buttonPanel.add(b5);
          t1 = new JTextField ("0",3);               //JTextField contains empty string
          t2 = new JTextField ("0",3);
          t3 = new JTextField ("0",3);
          t4 = new JTextField ("0",3);
          t5 = new JTextField ("0",3);
          t1.setEditable( false );
          t2.setEditable( false );
          t3.setEditable( false );
          t4.setEditable( false );
          t5.setEditable( false );
          responsePanel.setLayout(new GridLayout(5,1));
          responsePanel.add(t1);
          responsePanel.add(t2);
          responsePanel.add(t3);
          responsePanel.add(t4);
          responsePanel.add(t5);
          questionPanel.setLayout(new GridLayout(4,1));
          questionPanel.add(label1);
          questionPanel.add(q1);
          questionPanel.add(q2);
          questionPanel.add(q3);
          centerPanel.add(buttonPanel,BorderLayout.CENTER);
          centerPanel.add(responsePanel,BorderLayout.EAST);
          container.add(centerPanel,BorderLayout.WEST);
          container.add(questionPanel,BorderLayout.NORTH);
          q1.addActionListener(
               new ActionListener(){
          public void actionPerformed( ActionEvent e )
{                                        //actionPerformed of all registered listeners
          if (e.getSource() == b1) {
               que1[0] = Integer.parseInt(t1.getText()) + 1;
               String temp1 = String.valueOf(que1[0]);
          t1.setText(temp1);
          else if (e.getSource() == b2)     {
               que1[1] = Integer.parseInt(t2.getText()) + 1;
               String temp2 = String.valueOf(que1[1]);
          t2.setText(temp2);
          else if (e.getSource() == b3)     {
               que1[2] = Integer.parseInt(t3.getText()) + 1;
               String temp3 = String.valueOf(que1[2]);
          t3.setText(temp3);
          else if (e.getSource() == b4)     {
               que1[3] = Integer.parseInt(t4.getText()) + 1;
               String temp4 = String.valueOf(que1[3]);
          t4.setText(temp4);
          else if (e.getSource() == b5)     {
               que1[4] = Integer.parseInt(t5.getText()) + 1;
               String temp5 = String.valueOf(que1[4]);
          t5.setText(temp5);
} //end action performed
          q2.addActionListener(
               new ActionListener(){
          public void actionPerformed( ActionEvent e )
{                                        //actionPerformed of all registered listeners
          if (e.getSource() == b1) {
               que2[0] = Integer.parseInt(t1.getText()) + 1;
               String temp6 = String.valueOf(que2[0]);
          t1.setText(temp1);
          else if (e.getSource() == b2)     {
               que2[1] = Integer.parseInt(t2.getText()) + 1;
               String temp7 = String.valueOf(que2[1]);
          t2.setText(temp7);
          else if (e.getSource() == b3)     {
               que2[2] = Integer.parseInt(t3.getText()) + 1;
               String temp8 = String.valueOf(que2[2]);
          t3.setText(temp8);
          else if (e.getSource() == b4)     {
               que2[3] = Integer.parseInt(t4.getText()) + 1;
               String temp9 = String.valueOf(que2[3]);
          t4.setText(temp9);
          else if (e.getSource() == b5)     {
               que2[4] = Integer.parseInt(t5.getText()) + 1;
               String temp10 = String.valueOf(que2[4]);
          t5.setText(temp10);
} //end action performed
          q3.addActionListener(
               new ActionListener(){
          public void actionPerformed( ActionEvent e )
{                                        //actionPerformed of all registered listeners
          if (e.getSource() == b1) {
               que3[0] = Integer.parseInt(t1.getText()) + 1;
               String temp11 = String.valueOf(que3[0]);
          t1.setText(temp11);
          else if (e.getSource() == b2)     {
               que3[1] = Integer.parseInt(t2.getText()) + 1;
               String temp12 = String.valueOf(que3[1]);
          t2.setText(temp12);
          else if (e.getSource() == b3)     {
               que3[2] = Integer.parseInt(t3.getText()) + 1;
               String temp13 = String.valueOf(que3[2]);
          t3.setText(temp13);
          else if (e.getSource() == b4)     {
               que3[3] = Integer.parseInt(t4.getText()) + 1;
               String temp14 = String.valueOf(que3[3]);
          t4.setText(temp14);
          else if (e.getSource() == b5)     {
               que3[4] = Integer.parseInt(t5.getText()) + 1;
               String temp15 = String.valueOf(que3[4]);
          t5.setText(temp15);
} //end action performed
}//end constructor test
public void itemStateChanged(ItemEvent item) {
//int state = item.getStateChange();
//if (q1 == item.SELECTED)
          public class ButtonPanel extends JPanel
               public ButtonPanel()
          public class CenterPanel extends JPanel
               public CenterPanel()
          public class QuestionPanel extends JPanel
               public QuestionPanel()
          public class ResponsePanel extends JPanel
               public ResponsePanel()
public static void main(String [] args)
     test surveyFrame = new test("Student Survey") ;
     surveyFrame.setSize( 500,300 );
     surveyFrame.setVisible(true);
     surveyFrame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
     }//end main
}//end class test

is not abstract and does not override abstract method actionPerformed
Oh, I see that the title of your post is an error message? Ok. Well, the test class is declared as implementing an ActionListener. That means the test class must have an actionPerformed() method. Your test class apparently does not.
It does not appear that the test class needs to implement ActionListener. You are using annonymous classes as listeners.

Is not abstract and does not override abstract method tablechanged

I will remove all the gui code to make it shorter, but my problem lies with my InteractiveTableModelListener.
public class Meet extends JPanel{
private static void createAndShowGUI() {
        JFrame frame = new JFrame("MEET_dataTable");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(new Meet(), BorderLayout.CENTER);
        frame.pack();
        frame.setVisible(true);
public class InteractiveTableModelListener implements TableModelListener {
     public void TableChanged(TableModelEvent evt) {
if (evt.getType() == TableModelEvent.UPDATE) {
      int column = evt.getColumn();
      int row = evt.getFirstRow();
      dataTable.setColumnSelectionInterval(column + 1, column + 1);
      dataTable.setRowSelectionInterval(row, row);
class InteractiveRenderer extends DefaultTableCellRenderer {
protected int interactiveColumn;
public InteractiveRenderer(int interactiveColumn) {
      this.interactiveColumn = interactiveColumn;
public Component getTableCellRendererComponent(JTable dataTable,
     Object value, boolean isSelected, boolean hasFocus, int row,
     int column)
Component c = super.getTableCellRendererComponent(dataTable, value, isSelected, hasFocus, row, column);
   if (column == interactiveColumn && hasFocus) {
     if ((Meet.this.tableModel.getRowCount() - 1) == row &&
        !Meet.this.tableModel.hasEmptyRow())
         Meet.this.tableModel.addEmptyRow();
    highlightLastRow(row);
return c;
public void highlightLastRow(int row) {
     int lastrow = tableModel.getRowCount();
if (row == lastrow - 1) {
      dataTable.setRowSelectionInterval(lastrow - 1, lastrow - 1);
else {
      dataTable.setRowSelectionInterval(row + 1, row + 1);
     dataTable.setColumnSelectionInterval(0, 0);
public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
            UIManager.put("swing.boldMetal", Boolean.FALSE);
            createAndShowGUI();
}As i say, i have removed all the gui code to make it shorter, but in this code i create the table and add all the model to it. I am being returned with the error
Meet.InteractiveTableModelListener is not abstract and does not override abstract method tableChanged(javax.swing.event.TableModelEvent)in javax.swing.event.TableModelListener
what would be causing this error?
Cheers

Sorry, just figured out my silly error, the method is tableChanged not TableChanged.
cheers
TOPIC CLOSED
Edited by: nick2price on Sep 11, 2008 7:08 AM

Is not abstract and does not override abstract method ERROR

Hello. I'm new at all this, and am attempting to recreate a sample code out of my book (Teach Yourself XML in 24 Hours), and I keep getting an error. I appriciate any help.
This is the Error that I get:
DocumentPrinter is not abstract and does not override abstract method skippedEntity(java.lang.String) in org.xml.sax.ContentHandler
public class DocumentPrinter implements ContentHandler, ErrorHandler
 ^This is the sourcecode:
import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.ErrorHandler;
import org.xml.sax.Locator;
import org.xml.sax.SAXParseException;
import org.xml.sax.XMLReader;
public class DocumentPrinter implements ContentHandler, ErrorHandler
// A Constant containing the name of the SAX parser to use.
private static final String PARSER_NAME = "org.apache.xerces.parsers.SAXParser";
public static void main(String[] args)
 // Check to see whether the user supplied any command line arguments. If not, print an error and exit.
 if (args.length == 0)
 System.out.println("No XML document path specified.");
 System.exit(1);
 // Create a new instance of the DocumentPrinter class.
 DocumentPrinter dp = new DocumentPrinter();
 try
 // Create a new instance of the XML Parser.
 XMLReader parser = (XMLReader)Class.forName(PARSER_NAME).newInstance();
 // Set the parser's content handler
 // parser.setContentHandler(dp);
 // Set the parsers error handler
 parser.setErrorHandler(dp);
 // Parse the file named in the argument
 parser.parse(args[0]);
 catch (Exception ex)
 System.out.println(ex.getMessage());
 ex.printStackTrace();
public void characters(char[] ch, int start, int length)
 String chars ="";
 for (int i = start; i < start + length; i++)
 chars = chars + ch;
System.out.println("Recieved characters: " + chars);
public void startDocument()
System.out.println("Start Document.");
public void endDocument()
System.out.println("End of Document.");
public void startElement(String namespaceURI, String localName, String qName, Attributes atts)
System.out.println("Start element: " + localName);
for (int i = 0; i < atts.getLength(); i++)
System.out.println(" Attribute: " + atts.getLocalName(i));
System.out.println(" Value: " + atts.getValue(i));
public void endElement(String namespaceURI, String localName, String qName)
System.out.println("End of element: " + localName);
public void startPrefixMapping(String prefix, String uri)
System.out.println("Prefix mapping: " + prefix);
System.out.println("URI: " + uri);
public void endPrefixMapping(String prefix)
System.out.println("End of prefix mapping: " + prefix);
public void ignorableWhitespace(char[] ch, int start, int length)
System.out.println("Recieved whitespace.");
public void processingInstruction(String target, String data)
System.out.println("Recieved processing instruction:");
System.out.println("Target: " + target);
System.out.println("Data: " + data);
public void setDocumentLocation(Locator locator)
// Nada
public void error(SAXParseException exception)
System.out.println("Parsing error on line " + exception.getLineNumber());
public void fatalError(SAXParseException exception)
System.out.println("Fatal parsing error on line " + exception.getLineNumber());
public void warning(SAXParseException exception)
System.out.println("Warning on line " + exception.getLineNumber());

Check to make sure that the arguments are consistent with your ContentHandler class. Probably the wrong type.
I think you forgot to include the skippedEntity method, it seems to be missing. Even if an implemented class has a method that you are not using, you still have to include the method in your code even if it doesn't do anything.
Message was edited by:
ChargersTule1

...is not abstract and does not override abstract method compare

Why am I getting the above compile error when I am very clearly overriding abstract method compare (ditto abstract method compareTo)? Here is my code -- which was presented 1.5 code and I'm trying to retrofit to 1.4 -- followed by the complete compile time error. Thanks in advance for your help (even though I'm sure this is an easy question for you experts):
import java.util.*;
 This program sorts a set of item by comparing
 their descriptions.
public class TreeSetTest
 public static void main(String[] args)
 SortedSet parts = new TreeSet();
 parts.add(new Item("Toaster", 1234));
 parts.add(new Item("Widget", 4562));
 parts.add(new Item("Modem", 9912));
 System.out.println(parts);
 SortedSet sortByDescription = new TreeSet(new
 Comparator()
 public int compare(Item a, Item b) // LINE CAUSING THE ERROR
 String descrA = a.getDescription();
 String descrB = b.getDescription();
 return descrA.compareTo(descrB);
 sortByDescription.addAll(parts);
 System.out.println(sortByDescription);
 An item with a description and a part number.
class Item implements Comparable
 Constructs an item.
 @param aDescription the item's description
 @param aPartNumber the item's part number
 public Item(String aDescription, int aPartNumber)
 description = aDescription;
 partNumber = aPartNumber;
 Gets the description of this item.
 @return the description
 public String getDescription()
 return description;
 public String toString()
 return "[descripion=" + description
 + ", partNumber=" + partNumber + "]";
 public boolean equals(Object otherObject)
 if (this == otherObject) return true;
 if (otherObject == null) return false;
 if (getClass() != otherObject.getClass()) return false;
 Item other = (Item) otherObject;
 return description.equals(other.description)
 && partNumber == other.partNumber;
 public int hashCode()
 return 13 * description.hashCode() + 17 * partNumber;
 public int compareTo(Item other) // OTHER LINE CAUSING THE ERROR
 return partNumber - other.partNumber;
 private String description;
 private int partNumber;
}Compiler error:
TreeSetTest.java:25: <anonymous TreeSetTest$1> is not abstract and does not over
ride abstract method compare(java.lang.Object,java.lang.Object) in java.util.Com
parator
 public int compare(Item a, Item b)
 ^
TreeSetTest.java:41: Item is not abstract and does not override abstract method
compareTo(java.lang.Object) in java.lang.Comparable
class Item implements Comparable
^
2 errors

According to the book I'm reading, if you merely take
out the generic from the code, it should compile and
run in v1.4 (assuming, of course, that the class
exists in 1.4). I don't know what book you are reading but that's certainly incorrect or incomplete at least. I've manually retrofitted code to 1.4, and you'll be inserting casts as well as replacing type references with Object (or the erased type, to be more precise).
These interfaces do exist in 1.4, and
without the generics.Exactly. Which means compareTo takes an Object, and you should change your overriding method accordingly.
But this raises a new question: how does my 1.4
compiler know anything about generics? It doesn't and it can't. As the compiler is telling you, those interfaces expect Object. Think about it, you want to implement one interface which declares a method argument type of Object, in several classes, each with a different type. Obviously all of those are not valid overrides.

Want to see combination of Purchase Order and A/P report at material level

Hello,
Anyone familiar with an InfoProvider that will show a combination of Purchase Order and A/P data combined?
I'm specifically looking for a source that includes the PO information at the Vendor / Material level with order value and quantity at the time the PO was created AND accounts payable data at the Vendor / Material level with the invoiced amount and quantity (which may vary for the PO amounts).
Thank you,
Jim

Hi
Have you seen all of the follwoing datasources......
http://help.sap.com/saphelp_nw04/helpdata/en/df/fbb0d62f3a794d98d23609d17e1610/frameset.htm
Hope this helps
Regards
N Ganesh

Product is not abstract and does not override abstract method

Received the following errors.
Product.java:3: Product is not abstract and does not override abstract method ge
tDisplayText() in Displayable
public class Product implements Displayable
^
Product.java:16: getDisplayText() in Product cannot implement getDisplayText() i
n Displayable; attempting to use incompatible return type
found : void
required: java.lang.String
public void getDisplayText()
^
2 errors
Code reads as follows
import java.text.NumberFormat;
public class Product implements Displayable
     private String code;
     private String description;
     private double price;
     public Product()
          this.code = "";
          this.description = "";
          this.price = 0;
public void getDisplayText()
String message =
"Code: " + code + "\n" +
"Description: " + description + "\n" +
"Price: " + this.getFormattedPrice() + "\n";
     public Product(String code, String description, double price)
          this.code = code;
          this.description = description;
          this.price = price;
     public void setCode(String code)
          this.code = code;
     public String getCode(){
          return code;
     public void setDescription(String description)
          this.description = description;
     public String getDescription()
          return description;
     public void setPrice(double price)
          this.price = price;
     public double getPrice()
          return price;
     public String getFormattedPrice()
          NumberFormat currency = NumberFormat.getCurrencyInstance();
          return currency.format(price);
Please help!

Received the following errors.
Product.java:3: Product is not abstract and does not
override abstract method ge
tDisplayText() in Displayable
public class Product implements Displayable
^
Product.java:16: getDisplayText() in Product cannot
implement getDisplayText() i
n Displayable; attempting to use incompatible return
type
found : void
required: java.lang.String
public void getDisplayText()
^
2 errors
Code reads as follows
Please use the code tags when posting code. There is a code button right above the text box where you enter your post. Click on it and put the code between the code tags.
These error messages are quite clear in telling what is wrong. You have an Interface called Displayable that specifies a method something like thispublic String getDisplayText() {But in your Product source code, you created thismethodpublic void getDisplayText() {The compiler is complaining because the methods are not the same.
You also need to return a String in the method probalby like thisreturn message;

Some questions on versioning and synchronizing metadata

Hy all!
I am quite new to warehousing and Oracle Warehouse Builder, and so i would have some questions regarding on some common issues. I would appriciate if you guys would who have experience in this domain to share some good practice knowledge :)
I am using OWB 10.2
So first of all i would like to know if you have some proposal of the way of versioning control and synchronizing projects between team memebers when working on a bigger project, team memebers that don't work on the same repository (cause i saw that OWB has an integrated multiuser support for handeling object locks and user sessions).
I saw that a way of migrating data from one place to a nother is using the import/export options integrated in OWB. This creates mdl files wich are some kind of "dumps" of the metadata informations, but the thing with these mdl files wich i don't think is a good way to synchronize is that first of all the .mdx and .xml files contained in the .mdl (wich is kind of a zip) contains many informations in it (like creation date, some timestamps, etc) wich are always updated when exporting, and if synchronizing these files maybee using CVS, we always will get differences between the files alltough they would contain the same thing, only timestamps changed.
Then a nother issue with this, is that we could have 2 alternatives: dump the whole project, wich is odd to have to synchronize a single file between users, especialy on a big project, then the orher way would be doing for each object from the project (each mapping, each table, etc) an separate .mdl filem then to synchronize each file of each object, wich will be unefficient on reimporting each file in part.
So please if you can share the way you work on a big project with many implementers with OWB, i would really appriciate.
A nother thing i would like to know is: is there a way to generate from an existing project (like one created with OWB) the OMB commands dump (maybee in a tcl script)? Cause i saw that the way the exeprienced users implement warehousing is using TCL with OMB language. I downloaded the example from oracle for warehouse project, and i saw that is entirely made from tcl scripts (so no mdl file involved). And this i think would be nice, to have the OMB commands generated from an existing projects.
I see this OWB projects like a database wich can be built up from only OMB commands and OWB a graphical tool to do this (same as constructing a database only from DDL commands or using SQL developer to do this), this is why i am asking about a way of dumping the OMB commands for creating an OWB project.
Please give me some advices, and correct me if i sad some dumb things :D but i really am new to warehousing and i would really appriciate if you guys with experience could share some informations.
Thank you verry much!
Alex21

Depends. Having everyone working on the same project certainly simplifies things a lot regarding merging and is generally my preference. But I also recognize that some projects are complex enough that people wind up stepping on each other's toes if this is the case. In those cases, though, I try to minimize the issue of merging changes by having common structural objects (code libraries, tables, views, etc) retained in a single, strictly controlled, central project schema and having the developer's personal work areas reference them by synonym, thus being unable to alter them to the detriment of others.
If they want to change a common object then need to drop their synonym and make a local copy which they can alter, and then there is a managed process by which these get merged back into the main project schema.
This way any changes MUST go through a central schema, we can put processes in place to notify all of the team of any impending changes, and can also script updates across the team.
Every hour a script runs automatically that checks for dropped synonyms and notifies the project leader. It especially checks for two developers who have built local copies of the same object and notifies each that they need to coordinate with each other as they are risking a conflict. When a structural change is submitted back to the central shared schema, it is added to a batch that is installed at end of business and a list of those impending changes is circulated to the team along with impact analysis for dependencies. The install script updates the main schema, then also drops the local copy of the object in the developer's schema who made the change and re-establishes the synonym there to get back to status quo for the change monitoring. Finally, it then updates itself in all of the developer areas via OMBPlus. So, each morning the developers return to an updated and synched environment as far as the underlying structure.
This takes care of merging structural issues, and the management of the team should minimize other metadata merging by managing the worklist of who is to be working on a given mapping or process flow at a given time. Anyone found to be doing extraneous changes to a mapping or process flow when it is not in their job queue without getting pre-approval will be spoken to VERY firmly as this is counter to policy. And yes, OWB objects such as mappings are then also coordinated to the central project via import/export. OMBplus scripts also propogate these changes daily across the team as well.
Yep, there is a whole lot of scripting involved to get set up.... but it saves a ton of time merging things and solvinv conflicts down the road.
Cheers,
Mike

Illegal combination of modifiers: abstract and synchronized

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