Is it required to nullify strings in finally java?

I am working on j2ee web application. is it required to nullify strings in finally java, otherwise what will be the impact? ?

900605 wrote:
Lets talk about objects now.
If i create an object and left without nullifying then it stays in memory till garbage collector is called.
What happens if i nullify in finally? will the memory is cleared or in this case also just link(Object pointing) is cleared and it occupy memory still the garbage collector is called?In addition to what EJP said, make sure you understand that it is not possible to "nullify" an Object. Objects can never be null, only references can.
When you do x = null; you're not "clearing an object." You're just setting a reference variable to null, with the only direct result being that whatever object that reference previously pointed to now has one less reference pointing to it.

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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

Incompatible types required boolean found string

I am trying to set a value for a variable called Location when ever the value for the location is "AFRICA"
I need to reset it to be "55555".
What I am getting is that 'Incompatible types required boolean found string' under the if statemant. Can anyone shade some light on this?
String Location = filename.substring(12,17);
String AP = "AFRICA";
System.out.println(Location);
if (Location = AP)
System.out.println(Location);
Location = "55555";
thanks

rp0428 wrote:
The IF condition needs to be a BOOLEAN. The '=' is used to do an assignment. The boolean would be '=='.
But to compare strings why aren't you using
if (Location.equalsIgnoreCase(AP) {
To stress this a little more:
<tt>==</tt> applied between References will compare the Adresses they point to. This means this will only be true if both References point to the identical Object. @Test
testStringEquality(){
String s1 = "my Test"
String s2 = "Test"
Assert.assertTrue("This strings are equal",s1.equals("my "+s2));
Assert.assertFalse("This strings are not identical",s1 == ("my "+s2));
}So use <tt>==</tt> only for primitive number types (those starting with a lower case letter).
bye
TPD

How are strings immutable in java

for e.g.
String x="abc";
x+="DEF";
x=x.toLowerCase()
System.out.println("String is "+x);
if u run the above code it prints -String is abcdef
If strings are immutable hows it possible

Try the following:
public class test
     public static final void main(String args[])
          final int MAXCOUNTER = 10000;
          String s = new String();
          long t1 = System.currentTimeMillis();
          for(int i = 0;i < MAXCOUNTER;i++)
               s += ".";
          t1 = System.currentTimeMillis() - t1;
          StringBuffer sb = new StringBuffer();
          long t2 = System.currentTimeMillis();
          for(int i = 0;i < MAXCOUNTER;i++)
               sb.append(".");
          t2 = System.currentTimeMillis() - t2;
          System.out.println("String: " + s);
          System.out.println("StringBuffer: " + sb.toString());
          System.out.println("Time elapsed creating a String containing " + MAXCOUNTER + " dots: " + t1 + "ms");
          System.out.println("Time elapsed creating a String containing " + MAXCOUNTER + " dots: " + t2 + "ms");
}You'll notice that the time elapsed when creating the string using the StringBuffer.append() method is a lot smaller than the time spent creating the string using the + String operator.
Why? Because each time the + operator is called, it returns a new String object. It can't modify the String object in which it is used. The same happens with other String operations. The StringBuffer.append() method actually really appends the dot to the end of the buffer, it doesn't create a new StringBuffer for that.
I think the constants pool is only used for the constants hard coded into the source code (the ones you write between double quotes inside the source code).
That's why it's preferred to use StringBuffers when you do many String operations.

How to get an XML string from a Java Bean without wrting to a file first ?

I know we can save a Java Bean to an XML file with XMLEncoder and then read it back with XMLDecoder.
But how can I get an XML string of a Java Bean without writing to a file first ?
For instance :
My_Class A_Class = new My_Class("a",1,2,"Z", ...);
String XML_String_Of_The_Class = an XML representation of A_Class ?
Of course I can save it to a file with XMLEncoder, and read it in using XMLDecoder, then delete the file, I wonder if it is possible to skip all that and get the XML string directly ?
Frank

I think so too, but I am trying to send the object to a servlet as shown below, since I don't know how to send an object to a servlet, I can only turn it into a string and reconstruct it back to an object on the server side after receiving it :
import java.io.*;
import java.net.*;
import java.util.*;
class Servlet_Message        // Send a message to an HTTP servlet. The protocol is a GET or POST request with a URLEncoded string holding the arguments sent as name=value pairs.
public static int GET=0;
public static int POST=1;
private URL servlet;
// the URL of the servlet to send messages to
public Servlet_Message(URL servlet) { this.servlet=servlet; }
public String sendMessage(Properties args) throws IOException { return sendMessage(args,POST); }
// Send the request. Return the input stream with the response if the request succeeds.
// @param args the arguments to send to the servlet
// @param method GET or POST
// @exception IOException if error sending request
// @return the response from the servlet to this message
public String sendMessage(Properties args,int method) throws IOException
    String Input_Line;
    StringBuffer Result_Buf=new StringBuffer();
    // Set this up any way you want -- POST can be used for all calls, but request headers
    // cannot be set in JDK 1.0.2 so the query string still must be used to pass arguments.
    if (method==GET)
      URL url=new URL(servlet.toExternalForm()+"?"+toEncodedString(args));
      BufferedReader in=new BufferedReader(new InputStreamReader(url.openStream()));
      while ((Input_Line=in.readLine()) != null) Result_Buf.append(Input_Line+"\n");
    else
      URLConnection conn=servlet.openConnection();
      conn.setDoInput(true);
      conn.setDoOutput(true);
      conn.setUseCaches(false);
      // Work around a Netscape bug
      conn.setRequestProperty("Content-Type","application/x-www-form-urlencoded");
      // POST the request data (html form encoded)
      DataOutputStream out=new DataOutputStream(conn.getOutputStream());
      if (args!=null && args.size()>0)
        out.writeBytes(toEncodedString(args));
//        System.out.println("ServletMessage args: "+args);
//        System.out.println("ServletMessage toEncString args: "+toEncodedString(args));
      BufferedReader in=new BufferedReader(new InputStreamReader(conn.getInputStream()));
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      out.flush();
      out.close(); // ESSENTIAL for this to work!
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// Encode the arguments in the property set as a URL-encoded string. Multiple name=value pairs are separated by ampersands.
// @return the URLEncoded string with name=value pairs
public String toEncodedString(Properties args)
    StringBuffer sb=new StringBuffer();
    if (args!=null)
      String sep="";
      Enumeration names=args.propertyNames();
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        String name=(String)names.nextElement();
        try { sb.append(sep+URLEncoder.encode(name,"UTF-8")+"="+URLEncoder.encode(args.getProperty(name),"UTF-8")); }
//        try { sb.append(sep+URLEncoder.encode(name,"UTF-16")+"="+URLEncoder.encode(args.getProperty(name),"UTF-16")); }
        catch (UnsupportedEncodingException e) { System.out.println(e); }
        sep="&";
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}As shown above the servlet need to encode a string.
Now my question becomes :
<1> Is it possible to send an object to a servlet, if so how ? And at the receiving end how to get it back to an object ?
<2> If it can't be done, how can I be sure to encode the string in the right format to send it over to the servlet ?
Frank

Finding the key according to string length in java.util.Properties

Finding the key according to string length in java.util.Properties.
I know only String length only.

i need to retrieve the values from the java.util.properties.
we know that we need to give the key value in order to retrieve the datas.
but my problem is i will give the length of the key instead of giving the key value but i need to retrieve the datas according to the length of the key.

Use Enum to Switch on Strings where one string is a java reserved word.

Hi,
I'm having problems switching on a string using enums, when one of the strings is a java reserved word. Any suggestions would be appreciated. Or maybe even a suggestion that I should just be stringing together if-else if and doing string compares rather than a switch.
I've been using the following method to switch on strings.
public enum MyEnum
foo, bar, novalue;
public static MyEnum stringValue(String string)
try { return valueOf(string); }
catch (Exception e) { return novalue; }
Then I can switch like
switch(MyEnum.stringValue( someString )
case foo:
break;
case bar:
break;
default:
break;
Now I have run into the problem where one of the strings I need to use is "int", which is a reserved word in java, so I have to modify.
What is the best way to handle this?
I could just not add it to the Enum and handle it at the switch like this...
switch(MyEnum.stringValue( someString )
case foo:
break;
case bar:
break;
default:
if(someString.equals("int") { ... }
break;
OR...
I could change the Enum, and return intx, by checking if the string is "int". I could check before the valueOf, or during the exception, but I know it's not good practice to use Exceptions in the normal execution of your code... as it's not really an exception.
public enum MyEnum
foo, bar, intx, novalue;
public static MyEnum stringValue(String string)
if(string.equals("int") { return intx; }
try { return valueOf(string); }
catch (Exception e) { return novalue; }
OR...
public enum MyEnum
foo, bar, intx, novalue;
public static MyEnum stringValue(String string)
try { return valueOf(string); }
catch (Exception e) {
if(string.equals("int") { return intx; }
else return novalue;
}

My advice is still to not name the enum the same as the value of the string you want to test for. That page I linked to shows how to have enums with parameters. Then you could have an enum whose name is (say) JavaInt and whose string value is "int".
But frankly if I wanted to map Strings to actions I would just use a Map<String, Action> instead of trying to force my code into an antique construction like switch.

How to deocde a Base64 String in Sun Java ME SDK 3.0(Urgent)

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import com.sun.midp.io.Base64;
byte[] data = Base64.decode(EncodedString);
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Can you please let us know as how you solved the problem? Since we are developing a blackberry app, we found base64 class for blackberry development. We have plans of doing the same in android, not sure whether they have this. As long as we have generic base64 class that can be used in any client device, that would be great. I did a lot of research and could not fine. Please give us the solution.

How to return array of String to a java program.! ??

Hi All,
I am new to JNI programming. so trying with simple example. I am having one problem. I have one array of String in my Java program. I want to reverse all the elements in this array and want back this new array in the same form i.e. array of string. So how can I do this ??
Please guide me.....
The function of defination of array in my java code is
public native String[] getReverseStringArray(String[] arrString);
where as my array is like:
String[] arrStr = {"one", "two", "three", "four", "��","�c��","�J�^�J�i"};
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arrStr = employee.getReverseStringArray(arrStr);
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JNIEXPORT jobjectArray JNICALL
Java_Emp_getReverseStringArray (JNIEnv *env, jobject obj, jobjectArray arr)
// some code will come here......
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Thanx in advance...
Pandurang
[email protected]

Hi,
this is quite simple. Here an example function that works like this:
JNIEXPORT jobjectArray JNICALL Java_cadagent_ugopen_UgAssembly_jni_1getStructure
(JNIEnv *env, jclass cls, jstring part)
jobjectArray retvals = NULL;
jstring j_val = NULL;
int child_count = 5;
/* initialize return array */
j_val = (*env)->NewStringUTF(env, "");
retvals = (*env)->NewObjectArray(env, child_count, (*env)->FindClass(env, "java/lang/String"), j_val);
for (i=0;i<child_count;i++)
j_val = (*env)->NewStringUTF(env, "some text");
(*env)->SetObjectArrayElement(env, retvals,i, j_val);
return retvals;
Hope this answers you question.

Example of passing String Array from java to C using JNI

hi all
i searched net for passing string array from java to C but i dont get anything relevent
i have
class stu
int rollno
string name
String [] sub
i want to pass all as String array from java to C and access it C side

1. Code it as though it were being passed to another method written in java.
2. Redefine the method implementation to say "native".
3. Run jnih to generate a C ".h" file. You will see that the string array
is passed into C as a jobject, which can be cast to a JNI array.
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in the generated .h file.

How can I manage byte size of a string value in java?

Hi,
How can I manage byte size of a string value in java? I have NAME column in my database table, of type VARCHAR2(128). Supports multilingual, so value in Name can be English, French or Dutch.. like that. Byte size of English character is 1 and that of French is 2 and varies.. . Because of this reason I find difficulty in insert query. Please suggest solution.

But the event does not really have a size - you can export the photos and make the size pretty much what you want - while it is in iPhoto it is an event
I guess that iPhoto could report the size of the original photos as imported - or the size of the modified photos if exported as JPEGs - or the size of the modified photos if exported with a maximum dimension of 1080 - but the event simply is photos and does not have a "size" until you export it
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what is your puprose for knowing the size?
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LN

Delivery Completed Indicator is required at the time of Final Invoice Posti

Hi All,
I have requirement like whenever we post Invoice (Invoice Verification - MIRO) with final invoice check box with reference to PO (we are not posting any Goods Receipt for this PO or partial quantity is received and psoted GR for this PO), Delivery Completeion Indicator needs to be filled out (Tick Mark) in Purchase Order) automatically.
Kindly help me to get solution.
Kind note: I am working on ECC 5.0.
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Thanks,
Sudarsan

I got solution.

Help required- Searching Particular string in column

Hi,
I have a table by name temp and 2 values in the table. I'm using LIKE caluse to search a string. I'm getting output for some particular string. Please correct the below query for me.
I have given a table/data reference for you:
Create table temp(col1 varchar2(255));
insert into temp values ('Test_Scale_High');
1 row inserted
insert into temp values ('Test_Scale_High');
1 row inserted
commit;
select * from temp;
col1
Test_Scale_High
Test_Scale High
select * from temp where upper(col1) like '%TEST_SCALE%';
COL1
Test_Scale_High
Test_Scale High
select * from temp WHERE UPPER(COL1) LIKE '%TEST_SCALE_%';
COL1
Test_Scale_High
Test_Scale High
select * from temp WHERE UPPER(COL1) LIKE '%TEST_SCALE_H%';
No Row Selected
Thanks,
Santhosh.S

santhosh.shivaram wrote:
select * from temp;
col1
Test_Scale_High
Test_Scale High
select * from temp where upper(col1) like '%TEST_SCALE%';
COL1
Test_Scale_High
Test_Scale High
select * from temp WHERE UPPER(COL1) LIKE '%TEST_SCALE_%';
COL1
Test_Scale_High
Test_Scale High
If I understand your requirement correctly you need to escape the Wild Card '_'
Hope the following code helps:
SQL> set feedback on;
SQL> SELECT * FROM TEMP
2 /
COL1
Test_Scale_High
Test_Scale High
2 rows selected.
SQL> SELECT *
2    FROM temp
3   WHERE UPPER (col1) LIKE '%TEST_SCALE%'
4 /
COL1
Test_Scale_High
Test_Scale High
2 rows selected.
SQL> SELECT *
2    FROM temp
3   WHERE UPPER (col1) LIKE '%TEST_SCALE\_%' ESCAPE '\'
4 /
COL1
Test_Scale_High
1 row selected.
SQL> SELECT *
2    FROM temp
3   WHERE UPPER (col1) LIKE '%TEST_SCALE_H%'
4 /
COL1
Test_Scale_High
Test_Scale High
2 rows selected.
SQL> SELECT *
2    FROM temp
3   WHERE UPPER (col1) LIKE '%TEST_SCALE\_H%' ESCAPE '\'
4 /
COL1
Test_Scale_High
1 row selected.
SQL>Regards,
Jo
Edited by: Joice John : Added 2 Sample Codes

Help required on Datetime string conversion

Hello Experts,
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Mat

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If I offset and do the math myself, I have to handle various cases like different time zones as well as time closer to midnights( then the date has to be changed too ).
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Thanks again.
Mat

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Thanks,
Yim

What's Unicode 4 got to do with it? 1 characteris 1
character is 1 character.
strings now contain (and Java chars also) is
UTF-16 code units rather than Unicode characters
or
code points. Unicode characters outside the BMPare
encoded in Java as two or more code units. So it would seem that in some cases, a single
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represent it.So... you're saying that String.length() doesn't
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Is it required to nullify strings in finally java?

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