This is the simplest way i found.

Double num = 2.554545;

DecimalFormat twoDForm = new DecimalFormat("#.##");

return Double.valueOf(twoDForm.format(num));

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src : http://www.eukhost.com/forums/f33/tomcat-java-lang-outofmemoryerror-permgen-space-7675/

When you come across following error


java.lang.OutOfMemoryError: PermGen space



Follow the following steps :

1) vi /usr/local/jakarta/tomcat/bin/catalina.sh

2) Add following line into the catalina.sh file.

Quote:

JAVA_OPTS="-Djava.awt.headless=true -Dfile.encoding=UTF-8 -server -Xms512m -Xmx1024m -XX:NewSize=256m -XX:MaxNewSize=256m -XX:PermSize=256m -XX:MaxPermSize=256m -XX:+DisableExplicitGC"

Partial example of catalina.sh file

Quote:

=========================================== # JSSE_HOME (Optional) May point at your Java Secure Sockets Extension # (JSSE) installation, whose JAR files will be added to the # system class path used to start Tomcat. # # CATALINA_PID (Optional) Path of the file which should contains the pid # of catalina startup java process, when start (fork) is used # # $Id: catalina.sh 609438 2008-01-06 22:14:28Z markt $ # ----------------------------------------------------------------------------- JAVA_OPTS="-Djava.awt.headless=true -Dfile.encoding=UTF-8 -server -Xms512m -Xmx1024m -XX:NewSize=256m -XX:MaxNewSize=256m -XX:PermSize=256m -XX:MaxPermSize=256m -XX:+DisableExplicitGC" # OS specific support. $var _must_ be set to either true or false. cygwin=false os400=false darwin=false ========================================

Save and exit
Then restart the tomcat

Quote:

root@server[~]# /usr/local/jakarta/tomcat/bin/./shutdown.sh
root@server[~]# /usr/local/jakarta/tomcat/bin/./startup.sh
root@server[~]# /usr/local/jakarta/tomcat/bin/./catalina.sh run
root@server[~]# /scripts/restartsrv tomcat

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This, java.lang.ClassNotFoundException: [Ljava.lang.String is killing me a lot. I've suspected so many things about it, but actually is quite different. Its also mentioned in sun's bug database

Here are some of the solutions i've found in different sites;

1.http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6434149

This link recommends the following actions to solve this bug:

1) Add -Dsun.lang.ClassLoader.allowArraySyntax=true if you want to use a
library for which you don't have the source with JDK6

2) Change loader.loadClass( name ) to Class.forName( name, false, loader ) if
you own the code.

class org.apache.catalina.loader.WebAppClassLoader
uses this code to load classes:

clazz = loader.loadClass(name);

Can you please change the sections of code where this line is used (1352 and
others) to
clazz =  Class.forName( name, false, loader);

2. http://dev.bostone.us/2009/02/23/javaxfacesfacesexception-javalangclassnotfoundexception-ljavalangstring/

• jdk1.6 unlike 1.5 it will not attempt to load class (java.lang.String) by name by default
• it is easily solvable by locating JVM runtime in Eclipse's preferences (Window->Preferences->Installed JREs), highlighting the entry and adding runtime parameter -Dsun.lang.ClassLoader.allowArraySyntax=true

links:

• https://blog.coremedia.com/cm/post/2672591/RE_Java_6_javalangClassNotFoundException_LjavalangString_exception.html
• http://forums.java.net/jive/thread.jspa?threadID=15823

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Here is a simple secure MIME message sendMail function;

public boolean sendMail(String to, String subject, String text) {

Properties props = new Properties();

props.put("mail.transport.protocol", "smtp");

props.put("mail.smtp.host", Constants.SMTP_HOST_NAME);

props.put("mail.smtp.port", Constants.SMTP_HOST_PORT);

props.put("mail.smtp.auth", "true");

Authenticator auth = new SMTPAuthenticator();

Session mailSession = Session.getInstance(props, auth);

try{

Transport transport = mailSession.getTransport();

MimeMessage message = new MimeMessage(mailSession);

message.setFrom(new InternetAddress(Constants.SMTP_MESSAGE_SENDER));

message.addRecipient(Message.RecipientType.TO,

new InternetAddress(to));

message.setSubject(subject);

message.setHeader("MIM9

message.setHeader("Content-Type", "text/html");

message.setContent(text, "text/html");

transport.connect();

transport.sendMessage(message,

message.getRecipients(Message.RecipientType.TO));

transport.close();

return true;

} catch (MessagingException messagingException) {

messagingException.printStackTrace();

return false;

} catch (Exception exception){

exception.printStackTrace();

return false;

}

}

private class SMTPAuthenticator extends javax.mail.Authenticator {

public PasswordAuthentication getPasswordAuthentication() {

String username = Constants.SMTP_AUTH_USER;

String password = Constants.SMTP_AUTH_PWD;

return new PasswordAuthentication(username, password);

}

}

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if you are using trigger to generate sequence then might happened that the trigger is called twice. So to prevent from increasing the id value here is a little trick

CREATE OR REPLACE TRIGGER TRG_ABC BEFORE INSERT ON ABC
FOR EACH ROW
BEGIN
if :NEW.ID is null
then SELECT ABC_SEQ.NEXTVAL INTO :NEW.ID FROM DUAL;
end if;
END;

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http://www.xinotes.org/notes/note/422/

You can use the timestamp keyword to convert a string to Date:

select * from retail_transactions where posted_date >= timestamp '2008-12-01 00:00:00';

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Here are 5 Regular Expressions Every Web Programmer Should Know

http://immike.net/blog/2007/04/06/5-regular-expressions-every-web-programmer-should-know/

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