Tar + Gzip tooltip

Tar is used to combine the files together and Gzip is used to compress and uncompress the files.

Here is an example of its usage:

To create a tar file we can use the below lines:
$tar -cvf test.tar filesToBeCombined

To compress the tar ball we can use :
$gzip filesToBeCombined.tar

Spring 3 + Quartz 1.8.6 scheduler example

This is a very concise and simple example of implementing Quartz Jobs via Spring. Thanks mkyong!

http://www.mkyong.com/spring/spring-quartz-scheduler-example/

21 tips for productivity (Worth to try!)

1. Check emails in the afternoon. Use the morning for important work when you have more energy!

2. Stop waiting for perfect conditions

3. Big brave goals release energy

4. Mess creates stress

5. Sell your TV

6. Say goodbye to energy sapping vampires. Avoid negative people!

7. Make good habits such as when you do sports

8. Get up early

9. Don't do so many meetings

10. Don't say yes to every request

11. Outsource everything at which you're not the best in the world

12. Stop multi tasking

13. Get fit

14. Work out twice a day. 2 energy boosters!

15. Drink more water

16. Work in 90 minute blocks

17. Write a stop doing list

18. Use your commute time

19. Be contrarian

20. Right first time

21. Get lost! Have zero interruption focus time

How to set root password on Amazon EC2 instance

The default Amazon Linux EC2 instance does not allow root user login.
Use this first:
-sudo !!

or the traditional way
-sudo passwd root
and set the root password, then su - to get to root.

How to add xml resources in package using maven

By default maven does not include any files from "src/main/java" (${sourceDirectory} variable). You have two possibilities (choose one of them):

• put all your resource files (different than java files) to "src/main/resources" - recomended

http://stackoverflow.com/questions/9798955/with-maven-clean-package-xml-source-files-are-not-included-in-classpath

String pool management summary

package testPackage;
class Test {
       public static void main(String[] args) {
               String hello = "Hello", lo = "lo";
               System.out.print((hello == "Hello") + " ");
               System.out.print((Other.hello == hello) + " ");
               System.out.print((other.Other.hello == hello) + " ");
               System.out.print((hello == ("Hel"+"lo")) + " ");
               System.out.print((hello == ("Hel"+lo)) + " ");
               System.out.println(hello == ("Hel"+lo).intern());
       }
}
class Other { static String hello = "Hello"; }

and the compilation unit:

package other;
public class Other { static String hello = "Hello"; }

produces the output:

true true true true false true

This example illustrates six points:

• Literal strings within the same class in the same package represent references to the same String object.
• Literal strings within different classes in the same package represent references to the same String object.
• Literal strings within different classes in different packages likewise represent references to the same String object.
• Strings computed by constant expressions are computed at compile time and then treated as if they were literals.
• Strings computed by concatenation at run time are newly created and therefore distinct.

Ant reset property value

Ant works with "first setter wins principle"  Ant properties accept the FIRST setting of the property as the definitive one. Thereafter, future attempts to set the property will be ignored. Properties therefore are not variables, but more like manifest constant definitions.