Simple and Easy Codes

Java Threads - Wait and Notify Example

2012-02-07T23:31:00.000+05:30

This is a simple Thread example which demonstrates wait and notify functionality of a Thread. In this example we have a main class i.e. MainThread which will call AnotherThread, so that you can see both running simultaneously. Now our main thread enters into wait state till AnotherThread notifies it.

Please see the self explanatory code. Directly you can this code and see the output.

MainThread.java

/* MainThread.java */

public class MainThread {

public static void main(String[] args) {

//Start another thread
Thread anotherThreadObject = new Thread(new AnotherThread());
anotherThreadObject.start();

//Main thread continues
for(int i=0;i<10;i++) {

System.out.println(Thread.currentThread().getName()+" : "+i);

//this thread halts for 500 millisecond
try {
Thread.sleep(1 * 500);
} catch (InterruptedException e) {
e.printStackTrace();
}

//when counter reaches 5 wait for Other thread to notify it
if(i == 5) {
try {
synchronized(MainThread.class) {
System.out.println("MainThread is Waiting....");
MainThread.class.wait();
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}//for
}//main

}

AnotherThread.java

/* AnotherThread.java */

public class AnotherThread implements Runnable {

public void run() {

for(int i=0;i<10;i++) {

System.out.println(Thread.currentThread().getName()+" : "+i);

//this thread halts for 1 second

try {

Thread.sleep(1 * 1000);

} catch (InterruptedException e) {

e.printStackTrace();

}

//Now notify the main thread.

synchronized(MainThread.class) {

System.out.println("AnotherThread Notifying MainThread....");

MainThread.class.notify();

}

Output

Note : you may get below mentioned error, if you do not add synchronized block before calling wait menthod.

Exception in thread "main" java.lang.IllegalMonitorStateException

at java.lang.Object.wait(Native Method)

at java.lang.Object.wait(Object.java:485)

at test.MainThread.main(MainThread.java:25)

java.net.ConnectException: Connection timed out: connect

2012-01-17T13:29:00.000+05:30

 Exception in thread "main" java.net.ConnectException: Connection timed out: connect

    at java.net.PlainSocketImpl.socketConnect(Native Method)

    at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)

    at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)

    at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)

    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)

    at java.net.Socket.connect(Socket.java:529)

    at java.net.Socket.connect(Socket.java:478)

    at sun.net.NetworkClient.doConnect(NetworkClient.java:163)

    at sun.net.www.http.HttpClient.openServer(HttpClient.java:394)

    at sun.net.www.http.HttpClient.openServer(HttpClient.java:529)

    at sun.net.www.http.HttpClient.(HttpClient.java:233)

    at sun.net.www.http.HttpClient.New(HttpClient.java:306)

    at sun.net.www.http.HttpClient.New(HttpClient.java:323)

    at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:860)

    at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:801)

    at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:726)

    at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1049)

If you get above error, there could be one of the following reasons.

The domain/IP or port is incorrect
The domain/IP or port (i.e service) is down
The domain/IP is taking longer than your default timeout to respond
You have a firewall that is blocking requests or responses on whatever port you are using
You have a firewall that is blocking requests to that particular host
Your internet connection is down

I most of the cases there is a firewalls issue. Firewalls and port or IP blocking may be in place by your ISP. 

To access URL via Firewalls, you may require to set http.proxyHost and http.proxyPort. Try using below syntax.

System.setProperty("http.proxyHost", "host name");
System.setProperty("http.proxyPort", "port number");

Some time you may also get below error.

Exception in thread "main" java.io.IOException: Server returned HTTP response code: 403 for URL: http://www.google.com
    at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1313)

Here you may require to set User-Agent using below syntax.

connection.addRequestProperty("User-Agent", "Mozilla/4.0");

Please find the complete code below.

/* SimpleURLConnection.java */

import java.net.*;

import java.io.*;

public class SimpleURLConnection

{

    public static void main(String[] args) throws Exception

    {

        System.setProperty("http.proxyHost", "host name");

        System.setProperty("http.proxyPort", "port number");

        URL url= new URL("http://www.google.com");//provide proper url

        URLConnection connection = url.openConnection();

        connection.addRequestProperty("User-Agent", "Mozilla/4.0");

        BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));

        String line = "";

        while((line=in.readLine()) != null)

        {

            System.out.println(line);

        }

        //closing resource

        in.close();

        connection=null;

    }

}

Java : Compare two files

2012-01-13T19:22:00.000+05:30

Other day I was required to compare contents of two files in Java. Lets see how to compare two txt files in Java?

I was wondering if there is a Java APIs for Text file comparison, which will compare contents of two txt files using java program.

Basically the java program should mimc the behaviour of diff command of LINUX. diff is a file comparison utility that outputs the differences between two files. It is typically used to show the changes between one version of a file and a former version of the same file. Diff displays the changes made per line for text files.

Output of the java program should give same as result produced by diff command. I got many codes on net but they were not working as expected. Latter i got an idea, why not we can use diff command in our java program to produce the same result. But diff command works for LINUX, what is equivalent for Windows? Well i found COMP or FC are equivalent windows command for diff in LINUX. So with the help of these commands we can build a JAVA program which will compare contents of two txt files.

Lets see the code.

No need to add any jar file, directly you can run this code and see the output.

/* CompareFiles.java */

import java.io.BufferedReader;
import java.io.InputStreamReader;

public class CompareFiles {

    public void compare(String file1,String file2) {

        //For Windows
        runSystemCommand("fc /N \""+file1+"\" \""+file2+"\"");

        //For UNIX / LINUX
        //runSystemCommand("diff "+file1+" "+file2);
    }

    public void runSystemCommand(String command) {

        try {
            Process proc = Runtime.getRuntime().exec(command);

            BufferedReader inputStream = new BufferedReader(new InputStreamReader(proc.getInputStream()));
            BufferedReader errorStream = new BufferedReader(new InputStreamReader(proc.getErrorStream()));

            String strLn = "";

            // reading output stream of the command
            while ((strLn = inputStream.readLine()) != null) {
                System.out.println(strLn);
            }

            // reading errors of the command (if any)
            while ((strLn = errorStream.readLine()) != null) {
                System.out.println(strLn);
            }

        } catch (Exception e) {

            e.printStackTrace();
        }
    }

    public static void main(String[] args) {

        CompareFiles cf = new CompareFiles();

        cf.compare("C:\\file1.txt","C:\\file2.txt");
    }

}

UNIX / LINUX - HELP diff Command

2012-01-13T16:05:00.000+05:30

NAME
     diff - compare two files

SYNOPSIS
     diff [-bitw] [-c | -e | -f | -h | -n | -u] file1 file2

     diff [-bitw] [-C number | -U number] file1 file2

     diff [-bitw] [-D string] file1 file2

     diff [-bitw] [-c | -e | -f | -h | -n | -u] [-l] [-r] [-s] [-S name] directory1 directory2

DESCRIPTION
     The diff utility will compare the contents of file1 and file2 and write to standard output a list of changes necessary to convert file1 into file2. This list should be minimal.   Except in rare circumstances, diff finds a smallest sufficient set of file differences. No output will be produced if the files are identical.

     The normal output contains lines of these forms:

     n1 a n3,n4
     n1,n2 d n3
     n1,n2 c n3,n4

     where n1 and n2 represent lines file1 and n3 and n4 represent lines in file2 These lines resemble ed(1) commands to convert file1 to file2. By exchanging a for d and reading backward, file2 can be converted to file1. As in ed, identical pairs, where n1=n2 or n3=n4, are abbreviated as a single number.

     Following each of these lines come all the lines that are affected in the first file flagged by `<', then all the lines that are affected in the second file flagged by `>'.

OPTIONS
     The following options are supported:

     -b              Ignores trailing blanks (spaces and tabs) and   treats other strings of blanks as equivalent.

     -i              Ignores the case of letters. For example, 'A' will compare equal to 'a'.

     -t              Expands characters in output lines. Normal or -c output adds character(s) to the front of each line that may adversely affect the indentation of the original source lines and make the output lines difficult to interpret. This option will preserve the original source's indentation.

     -w              Ignores all blanks ( and characters) and treats all other strings of blanks   as   equivalent.    For    example, 'if ( a == b )'   will   compare   equal to 'if(a==b)'.

     The following options are mutually exclusive:

     -c              Produces a listing of differences with three lines of context. With this option, output format is modified slightly. That is, output begins with identification of the files involved and their creation dates, then each change is separated by a line with a dozen *'s. The lines removed from file1 are marked with '-'. The lines added to file2 are marked '+'. Lines that are changed from one file to the other are marked in both files with '!'.

     -C number       Produces a listing of differences identical to that produced by -c with number lines of context.

     -D string       Creates a merged version of file1 and file2 with C preprocessor controls included so that a compilation of the result without defining string is equivalent to compiling file1, while defining string will yield file2.

     -e              Produces a script of only a, c, and d commands for the editor ed, which will recreate file2 from file1. In connection with the -e option, the following shell program may help maintain multiple versions of a file. Only an ancestral file ($1) and a chain of version-to-version ed scripts ($2,$3,...) made by diff need be on hand. A ``latest version'' appears on the standard output. (shift; cat $*; echo '1,$p') | ed - $1

     -f              Produces a similar script, not useful with ed, in the opposite order.

     -h              Does a fast, half-hearted job. It works only when changed stretches are short and well separated, but does work on files of unlimited length. Options -c, -C, -D, -e, -f, and -n are unavailable with -h. diff does not descend into directories with this option.

     -n              Produces a script similar to -e, but in the opposite order and with a count of changed lines on each insert or delete command.

     -u              Produces a listing of differences with three lines of context. The output is similar to that of the -c option, except that the context is "unified". Removed and changed lines in file1 are marked by a '-' while lines added or changed in file2 are marked by a '+'. Both versions of changed lines appear in the output, while added, removed, and context lines appear only once. The identification of file1 and file2 is different, with "---" and "+++" being printed where "***" and "---" would appear with the -c option. Each change is separated by a line of the form @@ -n1,n2 +n3,n4 @@

     -U number       Produces a listing of differences identical to that produced by -u with number lines of context.

     The following options are used for comparing directories:

     -l              Produces output in long format. Before the diff, each text file is piped through pr(1) to paginate it.   Other differences   are remembered and summarized after all text file differences are reported.

     -r              Applies diff recursively to common subdirectories encountered.

     -s              Reports files that are identical. These identical files would not otherwise be mentioned.

     -S name         Starts a directory diff in the middle, beginning with the file name.

OPERANDS
     The following operands are supported:

     file1           A path name of a file or directory to be
     file2           compared. If either file1 or file2 is -, the standard input will be used in its place.

     directory1      A path name of a directory to be compared.
     directory2

     If only one of file1 and file2 is a directory, diff will be applied to the non-directory file and the file contained in the directory file with a filename that is the same as the last component of the non-directory file.

USAGE
     See largefile(5) for the description of the behavior of diff when encountering files greater than or equal to 2 Gbyte ( 2     **31 bytes).

EXAMPLES
     Example 1: Typical output of the diff command

     In the following command, dir1 is a directory containing a directory named x, dir2 is a directory containing a directory named x, dir1/x and dir2/x both contain files named date.out, and dir2/x contains a file named y:

     example% diff -r dir1 dir2
     Common subdirectories: dir1/x and dir2/x

     Only in dir2/x: y

     diff -r dir1/x/date.out dir2/x/date.out

     1c1

     < Mon Jul 2 13:12:16 PDT 1990

     ---

     > Tue Jun 19 21:41:39 PDT 1990

ENVIRONMENT VARIABLES
     See environ(5) for descriptions of the following environment variables that affect the execution of diff: LANG, LC_ALL, LC_CTYPE, LC_MESSAGES, LC_TIME, and NLSPATH.

     TZ       Determines the locale for affecting the timezone used for calculating file timestamps written with the -C and -c options.

EXIT STATUS
     The following exit values are returned:

     0        No differences were found.

     1        Differences were found.

     >1       An error occurred.

FILES
     /tmp/d?????             temporary file used for comparison

     /usr/lib/diffh          executable file for -h option

ATTRIBUTES
     See attributes(5) for descriptions of the following attributes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Availability                | SUNWesu                     |
    |_____________________________|_____________________________|
    | CSI                         | Enabled                     |
    |_____________________________|_____________________________|
    | Interface Stability         | Standard                    |
    |_____________________________|_____________________________|

SEE ALSO
     bdiff(1), cmp(1), comm(1), dircmp(1), ed(1), pr(1), sdiff(1), attributes(5), environ(5), largefile(5), standards(5)

NOTES
     Editing scripts produced under the -e or -f options are naive about creating lines consisting of a single period (.).

     Missing NEWLINE at end of file indicates that the last line of the file in question did not have a NEWLINE. If the lines are different, they will be flagged and output, although the output will seem to indicate they are the same.

COMP and FC : Windows equivalent of UNIX / LINUX diff command

2012-01-13T15:44:00.003+05:30

COMP and FC commands can be used as Windows equivalent of UNIX / LINUX diff command.

COMP

Compares the contents of two files or sets of files.

SYNTAX :

COMP [data1] [data2] [/D] [/A] [/L] [/N=number] [/C] [/OFF[LINE]]

  data1      Specifies location and name(s) of first file(s) to compare.

  data2      Specifies location and name(s) of second files to compare.

  /D         Displays differences in decimal format.

  /A         Displays differences in ASCII characters.

  /L         Displays line numbers for differences.

  /N=number  Compares only the first specified number of lines in each file.

  /C         Disregards case of ASCII letters when comparing files.

  /OFF[LINE] Do not skip files with offline attribute set.

To compare sets of files, use wildcards in data1 and data2 parameters.

FC

Compares two files or sets of files and displays the differences between them

SYNTAX:

FC [/A] [/C] [/L] [/LBn] [/N] [/OFF[LINE]] [/T] [/U] [/W] [/nnnn]

   [drive1:][path1]filename1 [drive2:][path2]filename2

FC /B [drive1:][path1]filename1 [drive2:][path2]filename2

  /A         Displays only first and last lines for each set of differences.

  /B         Performs a binary comparison.

  /C         Disregards the case of letters.

  /L         Compares files as ASCII text.

  /LBn       Sets the maximum consecutive mismatches to the specified

             number of lines.

  /N         Displays the line numbers on an ASCII comparison.

  /OFF[LINE] Do not skip files with offline attribute set.

  /T         Does not expand tabs to spaces.

  /U         Compare files as UNICODE text files.

  /W         Compresses white space (tabs and spaces) for comparison.

  /nnnn      Specifies the number of consecutive lines that must match

             after a mismatch.

  [drive1:][path1]filename1

             Specifies the first file or set of files to compare.

  [drive2:][path2]filename2

             Specifies the second file or set of files to compare.

Java : Simple LDAP program

2012-01-09T14:21:00.000+05:30

This is a simple LDAP program in java. Here we are using Netscape Directory SDK.To know more about Mozilla Netscape click here. To run this program you need to download ldapsdk.jar For Example ldapsdk-4.1.jar

To download ldapsdk-4.1.jar, click here. Provide appropriate data and see the output.

/* TestLDAP.java */

import java.util.Enumeration;

import netscape.ldap.LDAPAttribute;

import netscape.ldap.LDAPAttributeSet;

import netscape.ldap.LDAPConnection;

import netscape.ldap.LDAPEntry;

import netscape.ldap.LDAPException;

import netscape.ldap.LDAPSearchResults;

public class TestLDAP {

    public static void main(String[] args) {

        LDAPConnection ldConnection = null;

        LDAPEntry ldEntry = null;

        try {

            ldConnection = new LDAPConnection();

            String HOSTNAME = "HOSTNAME";

            int PORT = 389;

            String TREEBASE = "ou=PEOPLE,o=ha";//your DN

            //String QUERY = "(objectclass=* )";

            String QUERY = "(&(objectclass=objclass )(attribute=*value*))";

            ldConnection.connect( HOSTNAME, PORT );

            //String[] attrNames = {"*"};

            String[] attributeNames = {"val1","val2","val3","val4"};

            LDAPSearchResults ldSearchResult = ldConnection.search(TREEBASE,LDAPConnection.SCOPE_ONE,QUERY,attributeNames,false);

            if(ldSearchResult.hasMoreElements()) {

                ldEntry = ldSearchResult.next();

            }

            LDAPAttributeSet ldAttributeSet = ldEntry.getAttributeSet();

            Enumeration enumAttributeSet = ldAttributeSet.getAttributes();

            while(enumAttributeSet.hasMoreElements()) {

                LDAPAttribute ldAttribute = enumAttributeSet.nextElement();

                String attrName = ldAttribute.getName();

                String[] aVal = ldAttribute.getStringValueArray();

                System.out.println("----------------------");

                System.out.println("Key   : "+attrName);

                for(String val : aVal) {

                    System.out.println("Value : "+val);

                }

            }

        }

        catch(LDAPException LDAPex) {

            LDAPex.printStackTrace();

        }

    }

}

SQL0575N View or materialized query table "SCHEMA.TABLE_NAME" cannot be used because it has been marked inoperative. SQLSTATE=51024

2011-12-16T16:33:00.002+05:30

exceptionCOM.ibm.db2.jdbc.DB2Exception: [IBM][CLI Driver][DB2/SUN64] SQL0575N View or materialized query table "SCHEMA.TABLE_NAME" cannot be used because it has been marked inoperative. SQLSTATE=51024

OR

51024(-575)[IBM][CLI Driver][DB2/SUN64] SQL0575N View or materialized query table "SCHEMA.TABLE_NAME" cannot be used because it has been marked inoperative. SQLSTATE=51024
(0.45 secs)

If you get above exception in JAVA or while executing query in DB2, possible reason could be the view or materialized query table name has been marked inoperative because a table, view, alias, or privilege upon which it is dependent has been removed.

Please report this error to your database administrator so that they may grant privilege for that table, view or alias.

java.lang.IllegalArgumentException: Illegal pattern character 'AT'

2011-12-16T16:30:00.000+05:30

I got below mentioned error, while trying to add characters other than pre defined date pattern.

Exception in thread "main" java.lang.IllegalArgumentException: Illegal pattern character 'AT'
    at java.text.SimpleDateFormat.compile(SimpleDateFormat.java:769)
    at java.text.SimpleDateFormat.initialize(SimpleDateFormat.java:576)
    at java.text.SimpleDateFormat.(SimpleDateFormat.java:501)
    at java.text.SimpleDateFormat.(SimpleDateFormat.java:476)

To add your desire Characters or String you need to by-pass it using escape sequence. Please see the correct syntax below. Note the escape character single quote ('), whatever you want to pass a Characters or String need to by-pass it using escape character single quote (').

Correct Syntax:

Calendar cal = Calendar.getInstance();
SimpleDateFormat sdFormat = new SimpleDateFormat("yyyy-MM-dd 'AT' hh:mm:ss");
String strDate = sdFormat.format(cal.getTime());
System.out.println("Now : "+strDate);

Output:

Now : 2011-12-16 AT 03:57:40

A repository hook failed

2011-12-15T20:17:00.003+05:30

A repository hook failed
svn: Commit blocked by pre-commit hook (exit code 1) with output:
Please enter a log message to commit

I got above error while commiting my changes into SVN repository. As the error suggest "Please enter a log message to commit". Make sure you enter a message for commiting. It expects a message to commit, make sure that the message box is not left blank.

CLI0611E Invalid column name. SQLSTATE=S0022

2011-12-15T20:13:00.002+05:30

COM.ibm.db2.jdbc.DB2Exception: [IBM][JDBC Driver] CLI0611E Invalid column name. SQLSTATE=S0022
    at COM.ibm.db2.jdbc.app.SQLExceptionGenerator.rsException(Unknown Source)
    at COM.ibm.db2.jdbc.app.DB2ResultSet.findColumn(Unknown Source)
    at COM.ibm.db2.jdbc.app.DB2ResultSet.getString(Unknown Source)

As the get above error suggest, The column name specified in the Query or in resultSet is invalid.

resultSet.getString("COLUMN_NAME");

Please re-check all the column names against table name and make sure it is correct.

SQL1336N The remote host "serverX" was not found

2011-12-15T20:05:00.000+05:30

Exception in thread "main" COM.ibm.db2.jdbc.DB2Exception: [IBM][CLI Driver] SQL1336N  The remote host "serverX" was not found.

at COM.ibm.db2.jdbc.app.SQLExceptionGenerator.throw_SQLException(Unknown Source)

at COM.ibm.db2.jdbc.app.SQLExceptionGenerator.check_return_code(Unknown Source)

at COM.ibm.db2.jdbc.app.DB2Connection.connect(Unknown Source)

at COM.ibm.db2.jdbc.app.DB2Connection.(Unknown Source)

at COM.ibm.db2.jdbc.app.DB2Driver.connect(Unknown Source)

at java.sql.DriverManager.getConnection(DriverManager.java:582)

at java.sql.DriverManager.getConnection(DriverManager.java:185)

If you get above error, one possible reason could be the alias name used could be pointing to wrong database server.

Connection con=DriverManager.getConnection("jdbc:db2:ALIASNAME","username","password");

In my case ALIASNAME was required to point serverX but it was referring to serverY. I knew the solution but I did not know how to do it. I asked my database administrator (DBA) to have a look at the issue. What he told me is, he has to uncatalog and catalog it with the correct server.

Truly speaking I don’t know the meaning of these terms "uncatalog and catalog", I asked him let me know the solution as this issue may arise in future too. He told as i am a programmer, i cannot do the task which a DBA can do... Is it really?

So dear friends I may disappoint you and I apologize for that. But if this is the case with yours please contact with your database administrator.

Java : Simple way to get UTC/GMT date-time

2011-12-15T19:45:00.000+05:30

In Java when you create a new Date OR Calendar object, it is initialized to the current time but in the local timezone where the program is running. For example, for a program running in India, creates a TimeZone object based on Indian Standard Time.

In your java carrier you may need to get an UTC time (Coordinated Universal Time) or GMT time (Greenwich Mean Time). For this java provides a simple class known as TimeZone, which help us to get date/time from any geographical region accross the globe. All you need to do is pass correct time zone abbreviation.

To know more about TimeZone, see API.

Below are the examples of few time zone abbreviations

Abbr	Name	UTC offset
AKST	Alaska Standard Time	UTC−09
AST	Atlantic Standard Time	UTC−04
CET	Central European Time	UTC+01
CT	China Time	UTC+08
IST	Indian Standard Time	UTC+05:30
SGT	Singapore Time	UTC+08
UTC	Coordinated Universal Time	UTC

Get list of all time zone abbreviations, click here.

/* UTCDates.java */

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.TimeZone;

public class UTCDates {

    public static void main(String[] args) {

        Calendar cal = Calendar.getInstance();
        SimpleDateFormat sdFormat = new SimpleDateFormat("yyyy-MM-dd'T'hh:mm:ss");
        String strDate;

        sdFormat.setTimeZone(TimeZone.getDefault());
        strDate = sdFormat.format(cal.getTime());
        System.out.println("Now : "+strDate);

        sdFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
        strDate = sdFormat.format(cal.getTime());
        System.out.println("UTC : "+strDate);
    }

}

Output :

Now : 2011-12-15T05:25:22

UTC : 2011-12-15T11:55:22

Also Apache provides us an API to do this. To know more about it, click here.

You need to download commons-lang-x.x.jar and set it in classpath for example commons-lang-2.1.jar file.
To download commons-lang-x.x.jar, click here.

/* UTCDates.java */

import java.util.Calendar;

import org.apache.commons.lang.time.DateFormatUtils;

public class UTCDates {

    public static void main(String[] args) {

        Calendar cal = Calendar.getInstance();
        String strDate;

        strDate = DateFormatUtils.ISO_DATETIME_FORMAT.format(cal.getTime());
        System.out.println("Now : "+strDate);

        strDate = DateFormatUtils.formatUTC(cal.getTime(), DateFormatUtils.ISO_DATETIME_FORMAT.getPattern());
        System.out.println("UTC : "+strDate);
    }

}

More formats

FastDateFormat	Pattern
ISO_DATETIME_FORMAT	yyyy-MM-dd'T'HH:mm:ss
ISO_DATETIME_TIME_ZONE_FORMAT	yyyy-MM-dd'T'HH:mm:ssZZ
ISO_DATE_FORMAT	yyyy-MM-dd
ISO_DATE_TIME_ZONE_FORMAT	yyyy-MM-ddZZ
ISO_TIME_FORMAT	'T'HH:mm:ss
ISO_TIME_TIME_ZONE_FORMAT	'T'HH:mm:ssZZ
ISO_TIME_NO_T_FORMAT	HH:mm:ss
ISO_TIME_NO_T_TIME_ZONE_FORMAT	HH:mm:ssZZ
SMTP_DATETIME_FORMAT	EEE, dd MMM yyyy HH:mm:ss Z

SQL0206N, SQL0180N & SQL0408N

2011-12-09T11:50:00.000+05:30

I observed below mentioned error while working with DB2 query.

Error :
S0022(-206)[IBM][CLI Driver][DB2/SUN64] SQL0206N "2" is not valid in the context where it is used. SQLSTATE=42703
(0.58 secs)

Solution :
This error occurs when u try to compare OR assign values of different datatypes. For example COUNT = '2' will throw above error because COUNT is INT and you are trying to assing STRING to it. To avoid above error make sure datatypes are correct.

Error :

22007(-180)[IBM][CLI Driver][DB2/SUN64] SQL0180N The syntax of the string representation of a datetime value is incorrect. SQLSTATE=22007
(0.73 secs)

Solution :

This error occurs when working with DATETIME datatypes. Usually when assigning or comparing STRING to a DATETIME value.

If you need to compare / assign a STRING to DATETIME use below syntax.

DATETIME_VARIABLE = TIMESTAMP ('2011-12-08-15.49.26.000625')

Error :
22005(-408)[IBM][CLI Driver][DB2/SUN64] SQL0408N A value is not compatible with the data type of its assignment target. Target name is "DATETIME_VARIABLE". SQLSTATE=42821
(0.48 secs)

To convert a character string to a date or time value, you can use:

TIMESTAMP ('2002-10-20 12:00:00')
DATE ('2002-10-20')
DATE ('10/20/2002')
TIME ('12:00:00')
TIME ('12.00.00')

The TIMESTAMP(), DATE() and TIME() functions accept many other formats.

java.io.FileNotFoundException: log4j.xml (No such file or directory)

2011-12-07T19:47:00.000+05:30

If you get below mentioned error

log4j:ERROR Could not parse url [file:log4j.xml].
java.io.FileNotFoundException: log4j.xml (No such file or directory)
        at java.io.FileInputStream.open(Native Method)
        at java.io.FileInputStream.(FileInputStream.java:106)
        at java.io.FileInputStream.(FileInputStream.java:66)
        at sun.net.www.protocol.file.FileURLConnection.connect(FileURLConnection.java:70)
        at sun.net.www.protocol.file.FileURLConnection.getInputStream(FileURLConnection.java:161)
        at org.apache.xerces.impl.XMLEntityManager.setupCurrentEntity(Unknown Source)
        at org.apache.xerces.impl.XMLVersionDetector.determineDocVersion(Unknown Source)
        at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
        at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
        at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
        at org.apache.xerces.parsers.DOMParser.parse(Unknown Source)
        at org.apache.xerces.jaxp.DocumentBuilderImpl.parse(Unknown Source)
        at javax.xml.parsers.DocumentBuilder.parse(DocumentBuilder.java:180)
        at org.apache.log4j.xml.DOMConfigurator$2.parse(DOMConfigurator.java:612)
        at org.apache.log4j.xml.DOMConfigurator.doConfigure(DOMConfigurator.java:711)
        at org.apache.log4j.xml.DOMConfigurator.doConfigure(DOMConfigurator.java:618)
        at org.apache.log4j.helpers.OptionConverter.selectAndConfigure(OptionConverter.java:470)
        at org.apache.log4j.LogManager.(LogManager.java:122)
        at org.slf4j.impl.Log4jLoggerFactory.getLogger(Log4jLoggerFactory.java:73)
        at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:242)
        at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:254)
        at org.quartz.impl.StdSchedulerFactory.(StdSchedulerFactory.java:274)

Possible reason could be JVM is not able to find the provided file log4j.xml. Make sure the file is present in the location and You could pass the file in command line as shown below.

java -Dlog4j.configuration=file:/home/log4j.xml com.TestJava

OR add directly in your Java code.

System.setProperty("log4j.configuration", "/home/log4j.xml");

If you are using Eclipe IDE you can pass through VM arguments by steps shown below

Right click on Java -> Run As -> Run Configurations.. -> Arguments tab -> VM arguments

add the below code

-Dlog4j.configuration=file:/home/log4j.xml

Apply -> Run

SQLSTATE=42501

2011-12-07T19:26:00.002+05:30

If you get below mentioned error for DB2

42501(-551)[IBM][CLI Driver][DB2/SUN64] SQL0551N "USER" does not have the privilege to perform operation "SELECT" on object "SCHEMA.TABLE_NAME". SQLSTATE=42501 (0.48 secs)

As the error suggest your SQL administrator has not given privilege to perform SELECT operation on the particular table / View. Contact your SQL administrator and ask to grant privilege to perform operations on the table.

Invalid SQL syntax. SQLSTATE=37000

2011-12-07T19:25:00.002+05:30

If you get below mentioned error for DB2

37000(-99999)[IBM][CLI Driver] CLI0118E Invalid SQL syntax. SQLSTATE=37000 (0.03 secs)

As the error suggest, There could be a syntax error in the SQL. Please make sure that all the syntax for the SQL query is correct. Cross check for the syntax error.

Unresolved compilation problem

2011-12-07T18:31:00.000+05:30

Exception in thread "main" java.lang.Error: Unresolved compilation problem:
Unhandled exception type Exception

A java file cannot be ran unless and until it is compilation error free. JVM compiler understands any syntax error or compile time error before it could create runable byte code (.class file). Hence JVM can run a java program only after successful compilation. Look for the compile time error if you get above error.

JVM will run the code no matter if there is any run time exception. If there is any run time exception that will handled at run time accordingly. You must ensure that atleast a code do not contains any syntax error and is compileable.

How to solve compile error?

Solving compilation error is very simple, all you need to do is follow all rules and regulation of JVM. To solve compilation error you need to check for Syntax error, Scope of a variable, Non reachable statements, Exceptions handling etc

Solving compilation error is simple because it can be viewed. A simple Google search can solve your compilation error. Also IDEs like Eclipse, NetBeans etc has advance features which can show any compile error while wring the code itself i.e. before even compilation.

How to solve run time error/exceptions?

My personal experience says solving a RUN time error could me very tough in some cases. You may even require to spend overnight to solve a simple run time exceptions because it cannot be viewed by compiler. In most cases there is a data issue. Run time exception could be simply a null pointer exception which occurs because the object is null.

Example :

Code
System.out.println(tempStr.trim());
Can throw
Exception in thread "main" java.lang.NullPointerException
because tempStr is null.

The answer to the above question is debugging i.e. try to debug your code. Put logs wherever you doubt for the values. In the above example if you print the value of tempStr you will recognize the root cause of the exception. Also try to put exception handling codes i.e. try { .. } catch (Exception ex) {..} wherever you doubt for the values.

Source File Declaration Rules in Java

2011-12-07T17:41:00.000+05:30

C:\folder>javac test.java
test.java:9: class Test is public, should be declared in a file named Test.java
public class test
^
1 error

The above error appeared because the source file declaration rules in java says that If there is a public class in a file, the name of the file must match the name of the public class. For example, a class declared as public class Test { } must be in a source code file named Test.java. Also note that in Java everything is case-sensitive hence test and Test are treated as two different things.

Below are the rules associated with declaring classes, import statements, and package statements in a source file.

There can be only one public class per source code file.
Comments can appear at the beginning or end of any line in the source code file; they are independent of any of the positioning rules discussed here.
If there is a public class in a file, the name of the file must match the name of the public class. For example, a class declared as public class Test { } must be in a source code file named Test.java.
If the class is part of a package, the package statement must be the first line in the source code file, before any import statements that may be present.
If there are import statements, they must go between the package statement (if there is one) and the class declaration. If there isn't a package statement, then the import statement(s) must be the first line(s) in the source code file. If there are no package or import statements, the class declaration must be the first line in the source code file.
import and package statements apply to all classes within a source code file. In other words, there's no way to declare multiple classes in a file and have them in different packages, or use different imports.
A file can have more than one nonpublic class.
Files with no public classes can have a name that does not match any of the classes in the file

How to send mail using MAILX command in UNIX / LINUX

2011-12-07T17:17:00.003+05:30

Simple MAILX command

Below is the syntax to send simple mail using mailx command in UNIX / Linux.
You can use it as command line or used it in your shell script.

$ mailx -s "Mail Subject" test@xyz.com
type body of the mail
...
..
EOT (Ctrl+d)
$

Send attachment using MAILX command

In some cases you may have to send attachment in the mail. Lets see the syntax of sending an attachment using mailx command.

Below is the syntax to attach a file while sending a mail using mailx command in LINUX / UNIX

( cat /root/MailBody.txt
uuencode /root/file_name.txt file_name.txt
) | mailx -s "Mail Subject" test@xyz.com

Here file_name.txt is the attachment to be attached in the mail
AND MailBody.txt is the text body of the mail.

Simple Cryptography example in Java

2011-12-07T16:26:00.001+05:30

The Java security APIs span a wide range of areas, including cryptography, public key infrastructure, secure communication, authentication, and access control. Java security technology provides the developer with a comprehensive security framework for writing applications, and also provides the user or administrator with a set of tools to securely manage applications.
Source : http://www.oracle.com/technetwork/java/javase/tech/index-jsp-136007.html

javax.crypto.Cipher
This class provides the functionality of a cryptographic cipher for encryption and decryption. It forms the core of the Java Cryptographic Extension (JCE) framework.
Cipher API : http://docs.oracle.com/javase/6/docs/api/javax/crypto/Cipher.html

Cipher: initialized with keys, these used for encrypting/decrypting data. There are various types of algorithms: symmetric bulk encryption (e.g. AES, DES, DESede, Blowfish, IDEA)
http://docs.oracle.com/javase/6/docs/technotes/guides/security/crypto/CryptoSpec.html

Blowfish
Blowfish has a 64-bit block size and a variable key length from 1 bit up to 448 bits
Blowfish Wiki : http://en.wikipedia.org/wiki/Blowfish_%28cipher%29

To run this example you will need below mentioned JAR files in classpath.
jce.jar
rt.jar

However you dont have to download these JAR files, It is implicitly there within jre folder.
You can cross verify in JRE folder. Probably in "C:\Program Files\Java\jre6\lib"

Hence C:\Program Files\Java\jre6\lib\jce.jar and C:\Program Files\Java\jre6\lib\rt.jar are implicitly set in your classpath.

Below is the sample self explanatory Java program using Blowfish Cipher. Directly you can run the program and see output.

Simple Blowfish Cipher Example in java

/* SimpleCryptography.java */

import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

public class SimpleCryptography {

   private String AlgoName = "Blowfish";

    private String keyString = "DesireSecretKey";

    public String encrypt(String sValue) throws Exception {

       SecretKeySpec skeySpec = new SecretKeySpec(keyString.getBytes(), AlgoName);
       Cipher cipher = Cipher.getInstance(AlgoName);

       cipher.init(Cipher.ENCRYPT_MODE, skeySpec);

       byte[] encrypted = cipher.doFinal(sValue.getBytes());

        BASE64Encoder bASE64Encoder = new BASE64Encoder();
       String enStr = bASE64Encoder.encodeBuffer(encrypted);

       return enStr;
   }

   public String decrypt(String sValue) throws Exception {

       SecretKeySpec skeySpec = new SecretKeySpec(keyString.getBytes(), AlgoName);
       Cipher cipher = Cipher.getInstance(AlgoName);

       BASE64Decoder bASE64Decoder = new BASE64Decoder();
        byte decrytByt[] = bASE64Decoder.decodeBuffer(sValue);

        cipher.init(Cipher.DECRYPT_MODE, skeySpec);

        byte decrypted[] = cipher.doFinal(decrytByt);

        String deStr = new String(decrypted).trim();

       return deStr;
   }

   public static void main(String[] args) throws Exception {

       SimpleCryptography obj = new SimpleCryptography();

       String password = "MadanChaudhary";

       System.out.println("password : "+password);

       String encrypted_password = obj.encrypt(password);

       System.out.println("encrypted_password : "+encrypted_password);

       String decrypted_password = obj.decrypt(encrypted_password);

       System.out.println("decrypted_password : "+decrypted_password);

   }
}

Output :

password : MadanChaudhary
encrypted_password : 0LpwIuI0V+44sbZ5w3CCZw==

decrypted_password : MadanChaudhary

Below are the known Errors and exceptions I observed while writing this program.

1.
javax.crypto.IllegalBlockSizeException: Input length must be multiple of 8 when decrypting with padded cipher
    at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
    at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
    at com.sun.crypto.provider.BlowfishCipher.engineDoFinal(DashoA13*..)
    at javax.crypto.Cipher.doFinal(DashoA13*..)
Exception in thread "main" javax.crypto.IllegalBlockSizeException: Input length must be multiple of 8 when decrypting with padded cipher
    at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
    at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
    at com.sun.crypto.provider.BlowfishCipher.engineDoFinal(DashoA13*..)
    at javax.crypto.Cipher.doFinal(DashoA13*..)

2.
java.security.InvalidKeyException: Illegal key size or default parameters
    at javax.crypto.Cipher.a(DashoA13*..)
    at javax.crypto.Cipher.a(DashoA13*..)
    at javax.crypto.Cipher.a(DashoA13*..)
    at javax.crypto.Cipher.init(DashoA13*..)
    at javax.crypto.Cipher.init(DashoA13*..)
Exception in thread "main" java.security.InvalidKeyException: Illegal key size or default parameters
    at javax.crypto.Cipher.a(DashoA13*..)
    at javax.crypto.Cipher.a(DashoA13*..)
    at javax.crypto.Cipher.a(DashoA13*..)
    at javax.crypto.Cipher.init(DashoA13*..)
    at javax.crypto.Cipher.init(DashoA13*..)

3.
java.security.NoSuchAlgorithmException: Cannot find any provider supporting MyAlgo
    at javax.crypto.Cipher.getInstance(DashoA13*..)
Exception in thread "main" java.security.NoSuchAlgorithmException: Cannot find any provider supporting MyAlgo
    at javax.crypto.Cipher.getInstance(DashoA13*..)

4.
java.security.InvalidKeyException: Invalid key length: 16 bytes
    at com.sun.crypto.provider.DESCipher.engineGetKeySize(DashoA13*..)
    at javax.crypto.Cipher.b(DashoA13*..)
    at javax.crypto.Cipher.a(DashoA13*..)
    at javax.crypto.Cipher.a(DashoA13*..)
    at javax.crypto.Cipher.a(DashoA13*..)
    at javax.crypto.Cipher.init(DashoA13*..)
    at javax.crypto.Cipher.init(DashoA13*..)
Exception in thread "main" java.security.InvalidKeyException: Invalid key length: 16 bytes
    at com.sun.crypto.provider.DESCipher.engineGetKeySize(DashoA13*..)
    at javax.crypto.Cipher.b(DashoA13*..)
    at javax.crypto.Cipher.a(DashoA13*..)
    at javax.crypto.Cipher.a(DashoA13*..)
    at javax.crypto.Cipher.a(DashoA13*..)
    at javax.crypto.Cipher.init(DashoA13*..)
    at javax.crypto.Cipher.init(DashoA13*..)

5.
java.security.NoSuchAlgorithmException: Cannot find any provider supporting DSA
    at javax.crypto.Cipher.getInstance(DashoA13*..)
Exception in thread "main" java.security.NoSuchAlgorithmException: Cannot find any provider supporting DSA
    at javax.crypto.Cipher.getInstance(DashoA13*..)

6.
javax.crypto.BadPaddingException: Given final block not properly padded
    at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
    at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
    at com.sun.crypto.provider.BlowfishCipher.engineDoFinal(DashoA13*..)
    at javax.crypto.Cipher.doFinal(DashoA13*..)
Exception in thread "main" javax.crypto.BadPaddingException: Given final block not properly padded
    at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
    at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
    at com.sun.crypto.provider.BlowfishCipher.engineDoFinal(DashoA13*..)
    at javax.crypto.Cipher.doFinal(DashoA13*..)

7.
java.lang.IllegalStateException: Cipher not initialized
    at javax.crypto.Cipher.c(DashoA13*..)
    at javax.crypto.Cipher.doFinal(DashoA13*..)
Exception in thread "main" java.lang.IllegalStateException: Cipher not initialized
    at javax.crypto.Cipher.c(DashoA13*..)
    at javax.crypto.Cipher.doFinal(DashoA13*..)

8.
Exception in thread "main" java.security.InvalidKeyException: Illegal key size or default parameters
    at javax.crypto.Cipher.a(DashoA13*..)
    at javax.crypto.Cipher.a(DashoA13*..)
    at javax.crypto.Cipher.a(DashoA13*..)
    at javax.crypto.Cipher.init(DashoA13*..)
    at javax.crypto.Cipher.init(DashoA13*..)

9. Warnings

$javac SimpleCryptography.java

SimpleCryptography.java:6: warning: sun.misc.BASE64Decoder is Sun proprietary API and may be removed in a future release
import sun.misc.BASE64Decoder;
               ^
SimpleCryptography.java:7: warning: sun.misc.BASE64Encoder is Sun proprietary API and may be removed in a future release
import sun.misc.BASE64Encoder;
               ^
SimpleCryptography.java:24: warning: sun.misc.BASE64Encoder is Sun proprietary API and may be removed in a future release
        BASE64Encoder bASE64Encoder = new BASE64Encoder();
        ^
SimpleCryptography.java:24: warning: sun.misc.BASE64Encoder is Sun proprietary API and may be removed in a future release
        BASE64Encoder bASE64Encoder = new BASE64Encoder();
                                          ^
SimpleCryptography.java:35: warning: sun.misc.BASE64Decoder is Sun proprietary API and may be removed in a future release
                BASE64Decoder bASE64Decoder = new BASE64Decoder();
                ^
SimpleCryptography.java:35: warning: sun.misc.BASE64Decoder is Sun proprietary API and may be removed in a future release
                BASE64Decoder bASE64Decoder = new BASE64Decoder();
                                                  ^
6 warnings

A pseudo attribute name is expected.

2011-12-02T20:10:00.000+05:30

If you get below mentioned error

[Fatal Error] :1:54: A pseudo attribute name is expected.
Exception in thread "main" org.xml.sax.SAXParseException: A pseudo attribute name is expected.
    at org.apache.xerces.parsers.DOMParser.parse(Unknown Source)
    at org.apache.xerces.jaxp.DocumentBuilderImpl.parse(Unknown Source)
    at javax.xml.parsers.DocumentBuilder.parse(DocumentBuilder.java:124)

Possible reason could be the version and encoding information provided is not formatted correctly.
Please used the below syntax and try again.

?>

Note the ? at the end, I have missed that and it gave above error.

XML document structures must start and end within the same entity.

2011-12-02T20:06:00.000+05:30

If you get below mentioned error

[Fatal Error] :1:7717: XML document structures must start and end within the same entity.
Exception in thread "main" org.xml.sax.SAXParseException: XML document structures must start and end within the same entity.
    at org.apache.xerces.parsers.DOMParser.parse(Unknown Source)
    at org.apache.xerces.jaxp.DocumentBuilderImpl.parse(Unknown Source)
    at javax.xml.parsers.DocumentBuilder.parse(DocumentBuilder.java:124)

As the error suggest XML document is not formatted properly. Kindly go through the XML and look for any missing tags.

Indenting XML Output in Java

2011-12-02T17:59:00.007+05:30

Here is a simple JAVA program for Indenting / Formatting a long XML string. You can provide a XML as a string OR can provide XML from a file according to your requirement.

Formatting an XML can be useful for reading or just simply pretty printing it.

Here is a complete tested code you can directly run the program and see the output.

/* IndentXML.java */

import java.io.ByteArrayInputStream;

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;

import javax.xml.parsers.ParserConfigurationException;

import javax.xml.transform.OutputKeys;

import javax.xml.transform.Transformer;

import javax.xml.transform.TransformerException;

import javax.xml.transform.TransformerFactory;

import javax.xml.transform.dom.DOMSource;

import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.Document;

import org.xml.sax.SAXException;

public class IndentXML {

    public static void main(String[] args) throws ParserConfigurationException, SAXException, IOException, TransformerException 

    {

        //get the factory

        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

        //Using factory get an instance of document builder

        DocumentBuilder db = dbf.newDocumentBuilder();

        //providing XML string to be indented

        String xmlStringToIndent = "<AllEmployee><Employee><Name>Ram</Name><Designation>Programmer</Designation><Department>Development</Department></Employee><Employee><Name>Shyam</Name><Designation>TL</Designation><Department>Finanace</Department></Employee><Employee><Name>Geeta</Name><Designation>Manager</Designation><Department>HR</Department></Employee></AllEmployee>";

        //converting String to InputStream

        InputStream inStr = new ByteArrayInputStream(xmlStringToIndent.getBytes());

        Document doc = db.parse(inStr);

        //Output file

        File outputFile = new File("c:/indentedOutputXmlFile.xml");

        OutputStream outSrc = new FileOutputStream(outputFile);

        //creating a transformer

        TransformerFactory transFactory = TransformerFactory.newInstance();

        Transformer transformer  = transFactory.newTransformer();

        transformer.setOutputProperty(OutputKeys.ENCODING, "utf-8");

        transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "no");

        transformer.setOutputProperty(OutputKeys.INDENT, "yes");

        transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "5");

        transformer.transform(new DOMSource(doc), new StreamResult(outSrc));

        System.out.println("OutputFile created sucessfully!! "+outputFile.getPath());

    }

}

Input XML

String xmlStringToIndent = "<AllEmployee><Employee><Name>Ram</Name><Designation>Programmer</Designation><Department>Development</Department></Employee><Employee><Name>Shyam</Name><Designation>TL</Designation><Department>Finanace</Department></Employee><Employee><Name>Geeta</Name><Designation>Manager</Designation><Department>HR</Department></Employee></AllEmployee>";

Output XML

<?xml version="1.0" encoding="utf-8" standalone="no"?>
<AllEmployee>
     <Employee>
          <Name>Ram</Name>
          <Designation>Programmer</Designation>
          <Department>Development</Department>
     </Employee>
     <Employee>
          <Name>Shyam</Name>
          <Designation>TL</Designation>
          <Department>Finanace</Department>
     </Employee>
     <Employee>
          <Name>Geeta</Name>
          <Designation>Manager</Designation>
          <Department>HR</Department>
     </Employee>
</AllEmployee>

Note :

If you are passing XML string and it contains double quotes ("). Make to to bypass it by adding backward slash (\").

I observer below mentioned error when the string contained space in the beginning as show below.

String xmlStringToIndent = " <AllEmployee><Employee><Name>Ram</Name><Designation>Programmer ....."

Note the space in the beginning of the string. Make sure your XML is formatted properly.

Error

[Fatal Error] :1:7: The processing instruction target matching "[xX][mM][lL]" is not allowed.
Exception in thread "main" org.xml.sax.SAXParseException: The processing instruction target matching "[xX][mM][lL]" is not allowed.
    at org.apache.xerces.parsers.DOMParser.parse(Unknown Source)
    at org.apache.xerces.jaxp.DocumentBuilderImpl.parse(Unknown Source)
    at javax.xml.parsers.DocumentBuilder.parse(DocumentBuilder.java:124)
    at com.hewitt.hre.fadv.IndentXML.main(IndentXML.java:43)

SQLSTATE=42903

2011-11-25T18:37:00.001+05:30

I was in need to pass a max value in where condition. My folly, what i did is :

Incorrect : Select * from table_name where field = MAX(field);

Got below mentioned error in DB2

42903(-120)[IBM][CLI Driver][DB2/SUN64] SQL0120N Invalid use of an aggregate function or OLAP function. SQLSTATE=42903
(0.47 secs)

Correct :

Correct way is Inline Query

Select * from table_name where files = (Select MAX(filed) from table_name);

SQLSTATE=42601

2011-11-25T18:32:00.000+05:30

I was in need to fetch top n rows from a particular table in DB2. I got below mentioned error when tried with some incorrect syntax.

42601(-104)[IBM][CLI Driver][DB2/SUN64] SQL0104N An unexpected token "1" was found following "Select TOP ". Expected tokens may include: "". SQLSTATE=42601
(0.45 secs)

Correct Syntax :

Select * from table_name where filed = 'Some condition' order by field FETCH FIRST 10 ROWS ONLY;