Question on String and '+'

We all know String is not a primitive but actually a class in java, I guess. may be a wrapper class for char. array?
anyway, what makes it possible for '+' sign to work on string concat.? Java have no operator overload, as I rememeber. so what actually is done when 2 'Class' are 'added' with a '+' sign? is there any hidden feature?
Thanks for your time.
cynip.

We all know String is not a primitive but actually a
class in java, I guess. may be a wrapper class for
char. array?
anyway, what makes it possible for '+' sign to work on
string concat.? Java have no operator overload, as I
rememeber. so what actually is done when 2 'Class' are
'added' with a '+' sign? is there any hidden feature?
Thanks for your time.
cynip.The java compiler internally uses a StringBuffer to do string concatenation:
http://java.sun.com/docs/books/tutorial/java/data/stringsAndJavac.html

Similar Messages

Saving NSDatePicker to a string and saving that to NSUserDefaults...

Saving NSDatePicker to a string and saving that to NSUserDefaults I have it saved to a string then I have code that should save it to NSUSerDefaults so that when the program starts it is saved as the string not null. Here is the code [CODE]#import "MainView.h"
#import "DateView.h"
@implementation MainView
-(void)awakeFromNib
[self removeFromSuperview];
[self addSubview:dateView];
[dateView setdateandtime];
[dateView permsavedattime];
@end [/CODE] [CODE]#import "DateView.h"
#include "MainView.h"//Use #import this is to see if #include Works
@implementation DateView
-(IBAction)showuserdefaultdate
[self userdefaultdate];
//dateoutput.text =tddate;
-(void)permsavedattime
tddate=[prefs stringForKey:@"testing"];
tdtime=[prefs stringForKey:@"timetesting"];
dateoutput.text =[[NSString alloc] initWithFormat:@"%@",tddate];
-(void)userdefaultdate
prefs =[NSUserDefaults standardUserDefaults];
[prefs setInteger:tddate forKey:@"testing"];
[prefs setObject:tdtime forKey:@"timetesting"];
-(void)setdateandtime
[Today setDate:[NSDate date] animated:YES];
//formatting date style
dateformatter = [ [ NSDateFormatter alloc ] init ];
[ dateformatter setDateStyle:NSDateFormatterLongStyle];
[ dateformatter setTimeStyle:NSDateFormatterNoStyle ];//makes it so the time is not included
//[ formatter setTimeStyle:NSDateFormatterLongStyle ];//set to anystyle besides
//NoStyle if you dont want time included.
[Time setDate:[NSDate date] animated:YES];
//formatting date style
timeformatter = [ [ NSDateFormatter alloc ] init ];
[ timeformatter setDateStyle:NSDateFormatterNoStyle];//makes it so it doesn't get the date
[ timeformatter setTimeStyle:NSDateFormatterShortStyle];//makes it so the time is just hour and minute and A.M. or P.M.
//[ formatter setTimeStyle:NSDateFormatterLongStyle ];//set to anystyle besides
//NoStyle if you dont want time included.
-(IBAction)recieveDate
tddate= [dateformatter stringFromDate:Today.date];//Asigning the date to the string
dateoutput.text =tddate;
-(IBAction)recievetime
tdtime= [timeformatter stringFromDate:Time.date];//Asigning the date to the string
timeoutput.text =tdtime;
-(IBAction)canceltime
[Time setDate:[NSDate date] animated:YES];
tdtime= [timeformatter stringFromDate:Time.date];//Asigning the date to the string
timeoutput.text =tdtime;
-(IBAction)canceldate
[Today setDate:[NSDate date] animated:YES];
tddate= [dateformatter stringFromDate:Today.date];//Asigning the date to the string
dateoutput.text =tddate;
@end[/CODE] What am I missing? It keeps coming up Null I need it saved right so I can send it through email

softwarespecial wrote:
why can't I have the prefs saved in the .h
You can save that address in an ivar if you want to, but there's no purpose to that. The standardUserDefaults object is a +shared class object+. It's like a dictionary object that's maintained for your program by the NSUserPreferences class. You can read from or write to it at any time for the duration of your program. So whenever you get the shared object's address [NSUserDefaults standardUserDefaults], you're just getting the address of that same object each time.
In case the above doesn't make sense, I ran across a good explanation by Danneman in the last message on this page: [http://www.iphonedevsdk.com/forum/iphone-sdk-development/18716-set-settings-va riable-code.html].
When I did that as you so wisely pointed out it didn't work but when I saved it at each point I needed it it works.
When you change two things at once it's easy to forget the first and assume the second change solved the problem. Actually, I don't think saving prefs in your ivar had anything to do with your bug. What fixed it was getting a pointer to the shared std defaults object in this method:
-(void)permsavedattime
NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults]; <-- get the shared object
tddate=[prefs stringForKey:@"testing"];
tdtime=[prefs stringForKey:@"timetesting"];
dateoutput.text =[[NSString alloc] initWithFormat:@"%@",tddate];
Without the first line of the above, I'm fairly sure that your prefs ivar was nil. I didn't see any code that initialized that ivar prior to the first time userdefaultdate ran. It looked to me like permsavedattime ran at start up, well before prefs was set in userdefaultdate. If you're interested in backtracking, restore the file to the way it was when you posted, then add a NSLog() like this:
-(void)permsavedattime
// NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults]; <-- get the shared object
NSLog(@"prefs=%@", prefs);
tddate=[prefs stringForKey:@"testing"];
tdtime=[prefs stringForKey:@"timetesting"];
dateoutput.text =[[NSString alloc] initWithFormat:@"%@",tddate];
I wish to save lets say five different things to NSUSerDefaults would I be able to do it all with my NSUserDefaults prefs or would I have to create a another one for some of them?
You know the answer to your second question now, right? The important point is that you're never creating the shared object, you're just asking for its address whenever you need it.
Btw, there's another user defaults method you should know about: The synchronize method writes the data to disk. You might want to do that when your app is ready to exit. E.g., in the app delegate:
- (void)applicationWillTerminate:(UIApplication *)application {
NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
[prefs synchronize];
Although the docs suggest synchronize when the app is about to exit, I'm not sure it's necessary. I think the system might write the defaults out to disk anyway when the app terminates, but not sure about this. +User Defaults Programming Topics for Cocoa+ says:
On Mac OS X v10.5 and later, in applications in which a run-loop is present, synchronize is automatically invoked at periodic intervals. Consequently, you might synchronize before exiting a process, but otherwise you shouldn’t need to.
The above is in the iPhone edition, so I think it applies.
It might also be a good idea to update the data and call resetStandardUserDefaults in didReceiveMemoryWarning. I'm not clear about the need for reset either though, since the system may do that for you as well. But on a memory warning, you would definitely want to update the user default data if some of it is stored in an object to be released. You can find out how your app behaves on a memory warning by selecting Hardware->Simulate Memory Warning from the iPhone Simulator menu.
- Ray

Difference between String and final String

Hi friends,
This is Ramana. Can u suggest me in this Question
What is the difference between String and final String? Means
String str="hai";
final String str="hai";
Regards,
Ramana.

*******REPEAT POST***********
We already answered your question why post in a different section?
http://forum.java.sun.com/thread.jspa?threadID=5201549

Some questions on whitespace and &

Dear all,
I have some questions on whitespace and & that need you kind help:
1. Except /n /t /r and space, is there any characters that are whiteSpace characters?
2. When parsing XML document, when the ignorableWhitespace() method is called? Will it be called from characters() ?
e.g. Where the white space after <a> is called, and where is the white space between test1 and test 2 indied is called?
<a>
 test1 test2
</a> 3. When the & should be escaped in a well-formed (or validated) XML file by replacing &?
It should be excaped in any element content, such as test1 & test2 - except for <![CDATA[ section?
It should NOT always be used in attributes? e.g. <a b="test1 & test2"/> - has to do escaped by entity & - am I right?
Thanks!
Thanks


Thanks DrClap.
>
2. When parsing XML document, when the
ignorableWhitespace() method is called? Will it be
called from characters() ?It will be called when the document has a DTD and the
parser is a validating one that is actually
validating, when the parser sees whitespace that is
not part of a DTD element. It will not be called from
characters() because that is a method that you write.I wrote a contentHandler and using Xerces parser to parse an XML document. When I set validating feature to false, I found that for:
<a>
 test1 test2</a>The white space between <a> and (including newline) is actually called from characters(), not in ignorableWhitespace(). So does this mean that if validating - white space is always called from ignorableWhitespace(), and if not validating, if it is always called from characters()?
>
3. When the & should be escaped in a well-formed(or
validated) XML file by replacing &? The XML Recommendation says "The ampersand character
(&) and the left angle bracket (<) may appear
in their literal form only when used as markup
delimiters, or within a comment, a processing
instruction, or a CDATA section. If they are needed
elsewhere, they must be escaped using either numeric
character references or the strings "&" and
"<" respectively."So in this sense, both & in test1 & test2 and <a b="test1 & test2"/> is illegal unless replacing them by & - right? What does the markup delimiters mena in above XML Recommendation ? Example?
Thanks!

A question about JDBC and MySQL

hello dear friends,ask a question:
if in MySQL database, i have defined a clumon as TEXT data type.
when i use JDBC, i use which kind of java data type to hold TEXT,
i mean which getXXX() method i should use.
is it possible i just use getObject() and cast it to a binarystream??
thanks in advanced.

use this:
declare it 1st
String x ="";
then u can now get the value of the field...
x = getString("<fieldName>");is there length limitation?
for example, i want store a String which is got from a JTextArea, i also treat it as String and insert into the column with TEXT datatype like
insert table_name (text_column) values( string_1)
this works in JSP, should work in JAVA too...
hope i helped... ^_^

Field Symbols, Field String, and Field Group.

Hi,
Can you differentiate between filed symbols, field strings and field groups,
With regards,
Bharath Mohan B

Hi,
Field Symbols
Field symbols are placeholders or symbolic names for other fields. They do not physically reserve space for a field, but point to its contents. A field symbol cam point to any data object. The data object to which a field symbol points is assigned to it after it has been declared in the program.
Whenever you address a field symbol in a program, you are addressing the field that is assigned to the field symbol. After successful assignment, there is no difference in ABAP whether you reference the field symbol or the field itself. You must assign a field to each field symbol before you can address the latter in programs.
Field symbols are similar to dereferenced pointers in C (that is, pointers to which the content operator * is applied). However, the only real equivalent of pointers in ABAP, that is, variables that contain a memory address (reference) and that can be used without the contents operator, are reference variables in ABAP Objects.
All operations programmed with field symbols are applied to the field assigned to it. For example, a MOVE statement between two field symbols moves the contents of the field assigned to the first field symbol to the field assigned to the second field symbol. The field symbols themselves point to the same fields after the MOVE statement as they did before.
You can create field symbols either without or with type specifications. If you do not specify a type, the field symbol inherits all of the technical attributes of the field assigned to it. If you do specify a type, the system checks the compatibility of the field symbol and the field you are assigning to it during the ASSIGN statement.
Field symbols provide greater flexibility when you address data objects:
If you want to process sections of fields, you can specify the offset and length of the field dynamically.
You can assign one field symbol to another, which allows you to address parts of fields.
Assignments to field symbols may extend beyond field boundaries. This allows you to address regular sequences of fields in memory efficiently.
You can also force a field symbol to take different technical attributes from those of the field assigned to it.
The flexibility of field symbols provides elegant solutions to certain problems. On the other hand, it does mean that errors can easily occur. Since fields are not assigned to field symbols until runtime, the effectiveness of syntax and security checks is very limited for operations involving field symbols. This can lead to runtime errors or incorrect data assignments.
While runtime errors indicate an obvious problem, incorrect data assignments are dangerous because they can be very difficult to detect. For this reason, you should only use field symbols if you cannot achieve the same result using other ABAP statements.
For example, you may want to process part of a string where the offset and length depend on the contents of the field. You could use field symbols in this case. However, since the MOVE statement also supports variable offset and length specifications, you should use it instead. The MOVE statement (with your own auxiliary variables if required) is much safer than using field symbols, since it cannot address memory beyond the boundary of a field. However, field symbols may improve performance in some cases.
check the below links u will get the answers for your questions
http://help.sap.com/saphelp_nw04/helpdata/en/fc/eb3860358411d1829f0000e829fbfe/content.htm
http://www.sts.tu-harburg.de/teaching/sap_r3/ABAP4/field_sy.htm
http://searchsap.techtarget.com/tip/1,289483,sid21_gci920484,00.html
Syntax Diagram
FIELD-SYMBOLS
Basic form
FIELD-SYMBOLS <fs>.
Extras:
1. ... TYPE type
2. ... TYPE REF TO cif
3. ... TYPE REF TO DATA
4. ... TYPE LINE OF type
5. ... LIKE s
6. ... LIKE LINE OF s
7. ... TYPE tabkind
8. ... STRUCTURE s DEFAULT wa
The syntax check performed in an ABAP Objects context is stricter than in other ABAP areas. See Cannot Use Untyped Field Symbols ad Cannot Use Field Symbols as Components of Classes.
Effect
This statement declares a symbolic field called <fs>. At runtime, you can assign a concrete field to the field symbol using ASSIGN. All operations performed with the field symbol then directly affect the field assigned to it.
You can only use one of the additions.
Example
Output aircraft type from the table SFLIGHT using a field symbol:
FIELD-SYMBOLS <PT> TYPE ANY.
DATA SFLIGHT_WA TYPE SFLIGHT.
ASSIGN SFLIGHT_WA-PLANETYPE TO <PT>.
WRITE <PT>.
Addition 1
... TYPE type
Addition 2
... TYPE REF TO cif
Addition 3
... TYPE REF TO DATA
Addition 4
... TYPE LINE OF type
Addition 5
... LIKE s
Addition 6
... LIKE LINE OF s
Addition 7
... TYPE tabkind
Effect
You can define the type of the field symbol using additions 2 to 7 (just as you can for FORM parameters (compare Defining the Type of Subroutine Parameters). When you use the ASSIGN statement, the system carries out the same type checks as for USING parameters of FORMs.
This addition is not allowed in an ABAP Objects context. See Cannot Use Obsolete Casting for FIELD SYMBOLS.
In some cases, the syntax rules that apply to Unicode programs are different than those for non-Unicode programs. See Defining Types Using STRUCTURE.
Effect
Assigns any (internal) field string or structure to the field symbol from the ABAP Dictionary (s). All fields of the structure can be addressed by name: <fs>-fieldname. The structured field symbol points initially to the work area wa specified after DEFAULT.
The work area wa must be at least as long as the structure s. If s contains fields of the type I or F, wa should have the structure s or at least begin in that way, since otherwise alignment problems may occur.
Example
Address components of the flight bookings table SBOOK using a field symbol:
DATA SBOOK_WA LIKE SBOOK.
FIELD-SYMBOLS <SB> STRUCTURE SBOOK
DEFAULT SBOOK_WA.
WRITE: <SB>-BOOKID, <SB>-FLDATE.
Related
ASSIGN, DATA
Additional help
Declaring Field Symbols
FIELD GROUPS
are used to hold/handle large amount of data when the internal table are not useful
we use EXTRACT statement, HEADER structure in them
see the example
REPORT demo_extract.
NODES: spfli, sflight.
FIELD-GROUPS: header, flight_info, flight_date.
START-OF-SELECTION.
INSERT: spfli-carrid spfli-connid sflight-fldate
 INTO header,
 spfli-cityfrom spfli-cityto
 INTO flight_info.
GET spfli.
EXTRACT flight_info.
GET sflight.
EXTRACT flight_date.
END-OF-SELECTION.
SORT STABLE.
LOOP.
 AT FIRST.
 WRITE / 'Flight list'.
 ULINE.
 ENDAT.
 AT flight_info WITH flight_date.
 WRITE: / spfli-carrid , spfli-connid, sflight-fldate,
 spfli-cityfrom, spfli-cityto.
 ENDAT.
 AT flight_date.
 WRITE: / spfli-carrid , spfli-connid, sflight-fldate.
 ENDAT.
 AT LAST.
 ULINE.
 WRITE: cnt(spfli-carrid), 'Airlines'.
 ULINE.
 ENDAT.
ENDLOOP.
FIELD STRING is nothing but a string with one row of records.
Reward points if useful
regards
Anji

Using Strings and tokens . . .

Hello,
I was wondering if anyone could help me out with this problem(s). I'm designing a java program that (when a statement is typed in by a user) (1) tells you if it's a sentence, question, or exclamation, (2) it gives you the total amount of words in the statement, (3) tells you the longest word in the statement, (4)and also outputs the number of words that contain 1-3 characters. So far, i've been able to figure out how to do (1) and (2), but I'm really stuck on (3) and (4). Could someone please take a look at my program and tell me what I'm doing wrong. Thanks, Ana : )
// ProgramTwo.java Author: Ana
// Program Two. Demonstrates the use of strings and tokens.
import java.util.Scanner;
import java.io.*;
import java.util.StringTokenizer;
public class ProgramTwo
// Prints a string and various mutations of it.
public static void main (String[] args)
Scanner scan = new Scanner (System.in);
System.out.print("Enter a statement >");
String myString = scan.nextLine();
String oneWord;
if (myString.endsWith("!"))
System.out.println("Your statement ends with an exclamation.");
else
if (myString.endsWith("."))
System.out.println("Your statement is a sentence.");
else
System.out.println("Your statement is a question.");
StringTokenizer st = new StringTokenizer(myString);
System.out.println("There are " + st.countTokens() +
" word(s) in your statement.");
st = new StringTokenizer(myString);
while (st.hasMoreTokens())
oneWord = st.nextToken();
if (oneWord.length() <= 3)
System.out.println(oneWord); //supposed to determine the number of words that contain up to three
//characters
String longestWord = "";
while (st.hasMoreTokens())
String w = st.nextToken();
if (w.length() > longestWord.length())
longestWord = w;
System.out.print(longestWord); // It's supposed to determine the longest word in the statement
}

Hey Guys,
I just wanted to thank all of you who responded to my message. With your help, I was able to figure out a bunch of other stuff. ChuckBing, I replaced some parts like you said and it worked like a charm! KPSeal, you brought up a good point, I doubled checked with my instructor and he said it was Ok for me to leave that part as is. Lutha, thanks for your input. I was just wondering, is Python similar to Java? I've never heard of it before, then again I've never heard of Java until a couple of months ago : ) Anyways, thanks again!! Ana : )
By the way, here's how my program came out.
// ProgramTwo.java Author: Ana
// Program Two. Demonstrates the use of strings and tokens.
import java.util.Scanner;
import java.io.*;
import java.util.StringTokenizer;
public class ProgramTwo
// Prints and groups various word types and amounts.
public static void main (String[] args)
Scanner scan = new Scanner (System.in);
System.out.print("Enter a statement >");
String myString = scan.nextLine();
String oneWord;
if (myString.endsWith("!"))
System.out.println("Your statement ends with an exclamation.");
else
if (myString.endsWith("."))
System.out.println("Your statement is a sentence.");
else
System.out.println("Your statement is a question.");
StringTokenizer st = new StringTokenizer(myString);
System.out.println("There are " + st.countTokens() +
" word(s) in your statement.");
int shortWordCount = 0;
int medWordCount = 0;
int longWordCount = 0;
String longestWord = "";
String shortestWord = "";
while (st.hasMoreTokens())
oneWord = st.nextToken();
if (oneWord.length() <= 3)
shortWordCount++;
if (oneWord.length() >= 4 && (oneWord.length() <= 6))
medWordCount++;
if (oneWord.length() >= 7)
longWordCount++;
if (oneWord.length() > longestWord.length())
longestWord = oneWord;
if (oneWord.length() < shortestWord.length())
shortestWord = oneWord;
System.out.println("The shortest word is " + shortestWord + ".");
System.out.println("The longest word is " + longestWord + ".");
System.out.println("There are " + shortWordCount + " short words.");
System.out.println("There are " + medWordCount + " medium words.");
System.out.println("There are " + longWordCount + " long words.");

To differenciate string and list types in Xpress language

Hi! I have a question in Xpress language:
I'd like to know how to differentiate between string and list types. For example, *<s>orange</s>* and *<list><s>orange<s></list>*
How does it know Xpress language what is it string or list?
Thanks a lot.
P.D. Excuse for the strike text, I don't know why it shows striked test.

Try this:
<instanceof name='List'>
<ref>orange</ref>
</instanceof>
Edited by: Mindie on Mar 28, 2008 8:12 AM
Edited by: Mindie on Mar 28, 2008 8:13 AM
Edited by: Mindie on Mar 28, 2008 8:13 AM
Edited by: Mindie on Mar 28, 2008 8:13 AM

Little help with EL: concat static string and databound number

Hi OTN,
I'm a bit stuck with a simple - as I thought - case: concatenating static string and databound number in EL:
I have a deffered expression like:
#{1 != 2 ? ('Number is ' bindings.SomeNumber.inputValue) : 'no number'}
1 and 2 are databound values too but the question is about showing "Number is 5" where 5 is a SomeNumber.
Expression editor shows error on 'Number is'. And the error dissapperars if I remove "bindings.SomeNumber.inputValue".
How can I concatenate them?
Thanks.

Another option for you is to write that formatting logic in a static utility classes that takes parameters to return strings.
Ex.:
*/WEB-INF/utils.tld:*
<taglib xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-jsptaglibrary_2_1.xsd" version="2.1" xmlns="http://java.sun.com/xml/ns/javaee">
<description>utils</description>
<display-name>utils</display-name>
<tlib-version>1.0</tlib-version>
<short-name>utils</short-name>
<uri>http://biz.com/utils</uri>
<function>
 <name>getFormattedNumber</name>
 <function-class>com.mybiz.FormatUtils</function-class>
 <function-signature>java.lang.String getFormattedNumber(oracle.jbo.domain.Number)</function-signature>
</function>
</taglib>And then you use them in your EL expression like this:
page.jspx:_
<jsp:root xmlns:jsp="http://java.sun.com/JSP/Page" version="2.1" xmlns:f="http://java.sun.com/jsf/core"
 xmlns:af="http://xmlns.oracle.com/adf/faces/rich"
 xmlns:utils="http://biz.com/utils">
<af:outputText value="#{utils:getFormattedNumber(bindings.Number.inputValue)}"/>
</jsp:root>Better to have many options isn't it?

Differnce between null string and an empty string??

what is the major difference between null string and an empty string??
I wrote the following simple program and I could see some different output.
Other than that, any other differences that we should pay attention to???
C:\>java TestCode
Hello
nullHello
public class TestCode
     public static void main(String[] s)
     {     String s1 = "";
          String s2 = null;
          System.out.println(s1 + "Hello");
          System.out.println(s2 + "Hello");
}

There's a big difference between the two. A null String isn't pointing to an object, but an empty String is. For example, this is perfectly fine:
public class TestCode
    public static void main(String[] args)
        String s = "";
        System.out.println(s.length());
} It prints out 0 for the length of the String, just as it should. But this code will give you a NullPointerException:
public class TestCode
    public static void main(String[] args)
        String s = null;
        System.out.println(s.length());
} Since s isn't pointing to anything, you can't call its methods.

How to check empty string and null? Assign same value to multiple variables

Hi,
1.
How do I check for empty string and null?
in_value IN VARCHAR2
2. Also how do I assign same value to multiple variables?
var_one NUMBER := 0;
var_two NUMBER := 0;
var_one := var_two := 0; --- Gives an error
Thanks

MichaelS wrote:
Not always: Beware of CHAR's:
Bug 727361: ZERO-LENGTH STRING DOES NOT RETURN NULL WHEN USED WITH CHAR DATA TYPE IN PL/SQL:
SQL> declare
2    l_str1   char (10) := '';
3    l_str2   char (10) := null;
4 begin
5
6    if l_str1 is null
7    then
8      dbms_output.put_line ('oh STR1 is null');
9    elsif l_str1 is not null
10    then
11      dbms_output.put_line ('oh STR1 is NOT null');
12    end if;
13
14    if l_str2 is null
15    then
16      dbms_output.put_line ('oh STR2 is null');
17    elsif l_str2 is not null
18    then
19      dbms_output.put_line ('oh STR2 is NOT null');
20    end if;
21 end;
22 /
oh STR1 is NOT null
oh STR2 is null
PL/SQL procedure successfully completed.
SQL> alter session set events '10932 trace name context forever, level 16384';
Session altered.
SQL> declare
2    l_str1   char (10) := '';
3    l_str2   char (10) := null;
4 begin
5
6    if l_str1 is null
7    then
8      dbms_output.put_line ('oh STR1 is null');
9    elsif l_str1 is not null
10    then
11      dbms_output.put_line ('oh STR1 is NOT null');
12    end if;
13
14    if l_str2 is null
15    then
16      dbms_output.put_line ('oh STR2 is null');
17    elsif l_str2 is not null
18    then
19      dbms_output.put_line ('oh STR2 is NOT null');
20    end if;
21 end;
22 /
oh STR1 is null
oh STR2 is null
PL/SQL procedure successfully completed.
SQL> SY.

What is difference between Null String and Empty String ?

Hi
Just i have little confusion that the difference bet'n NULL String and Empty String ..
Please clear my doubte.
Thankx

For the same reason I think it's okay to say "null
String" and "empty String "as long as you know they
really mean "null String reference" and "empty String
object" respectively. Crap. It's only okay to say that as long as *the one you're talking to" knows what it really means. Whether you know it or not is absolutely irrelevant. And there is hardly any ambiguity about the effects that a statement like "assign an object to a reference" brings. "Null String" differs in that way.

Difference between null string and empty string??

what is the major difference between null string and an empty string??
I wrote the following simple program and I could see some different output.
Other than that, any other differences that we should pay attention to???
C:\>java TestCode
Hello
nullHello
public class TestCode
     public static void main(String[] s)
     {     String s1 = "";
          String s2 = null;
          System.out.println(s1 + "Hello");
          System.out.println(s2 + "Hello");
}

The difference is that an empty String is just empty but a null String has no value (i.e. it is not instantiated) this has signifigance since all Strings are objects.

Varchar2, empty strings and NULL

Hi all,
When inserting an empty string into a column of type varchar2 - is a NULL value stored in the column by the database? I've seen conflicting reports, and I know that the SQL 1992 spec specifies that empty strings not be treated as a NULL value, but that Oracle has traditionally treated zero length strings stored in a varchar2 column as NULL.
So, is there a way to store an empty string in a varchar2 column as an empty string and not a NULL value?
TIA,
Seth

It can be even more complicated or annoying than NULL not equal to ASCII NULL.
example:
create table test_null
(fld1 varchar2(10),
fld2 varchar2(10),
fld3 varchar2(20));
insert into test_null values (chr(0),null, 'chr(0) and null');
insert into test_null values (null, null, 'null and null');
insert into test_null values ('', chr(0), ''''' and chr(0)');
insert into test_null values ('', null, ''''' and null');
select * from test_null;
FLD1       FLD2       FLD3
                      chr(0) and null
                      null and null
                      '' and chr(0)
                      '' and null
1 DECLARE
2 BEGIN
3   for c1 in (select fld1, fld2, fld3 from test_null) loop
4      if c1.fld1 = c1.fld2 then
5         dbms_output.put_line(c1.fld3||' Are equal'||
6                ' Length fld1 = '||to_char(length(c1.fld1))||
7                ' Length fld2 = '||to_char(length(c1.fld2)));
8      else
9         dbms_output.put_line(c1.fld3||' Are NOT equal'||
10                ' Length fld1 = '||to_char(length(c1.fld1))||
11                ' Length fld2 = '||to_char(length(c1.fld2)));
12      end if;
13      dbms_output.put_line(' ');
14   end loop;
15* END;
SQL> /
chr(0) and null Are NOT equal Length fld1 = 1 Length fld2 =
null and null Are NOT equal Length fld1 = Length fld2 =
'' and chr(0) Are NOT equal Length fld1 = Length fld2 = 1
'' and null Are NOT equal Length fld1 = Length fld2 =
PL/SQL procedure successfully completed.

Question regarding battery and warranty

Hi all! I have a quick question about how and if my warranty applies to my battery. After about a year and a half of ownership (I have the three-year extended warranty), my battery has gone completely down the toilet. It wasn't a problem before, but this year I have to lug my T61p around a lot for lab work. My battery is now rated at... 39.75Wh when it shipped at 84.24Wh. This is a pretty drastic difference. In any case, I don't think that this is covered by warranty, but figured that I'd ask before I drop $180 on a new battery (ouch). And, speaking of, if my suspicions are correct, does anybody know where I might find a 9-cell battery for the T61p? All I'm seeing on Lenovo's website is the one for the N100... which doesn't... match very well. Yaknow.
Thanks a lot!
ThinkPad T61p [June 2008]: 2.5Ghz Penryn Core 2 Duo, 4GB DDR2 RAM, NVidia Quadro FX 570m 256MB, 160GB 7200RPM Fujitsu HDD, 1920x1200 WUXGA Matte LCD, Windows 7 RC1

Is either of these appropriate? I'm wary of the one on Amazon, as there are other (off-brand) batteries that are advertised as being Lenovo ones (though those generally sell for a lower price). The other one just looks like I'll have to call up to buy it.
http://www.amazon.com/Lenovo-43R9255-ThinkPad-Notebook-Battery/dp/B001DX9EKA
http://affordablepcsupply.com/products/IBM/REF/42T4511.html
Thoughts?
ThinkPad T61p [June 2008]: 2.5Ghz Penryn Core 2 Duo, 4GB DDR2 RAM, NVidia Quadro FX 570m 256MB, 160GB 7200RPM Fujitsu HDD, 1920x1200 WUXGA Matte LCD, Windows 7 RC1

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