How to fix Cannot change version of project facet Dynamic Web Module to 3.0 Error in Eclipse

Cannot change version of project facet Dynamic Web Module to 3.0

Today while converting Dynamic Web Project to Maven project I got below Error:

What steps I’ve performed to fix this?

In order to fix this first thing I did is to change Project Facets settings.

  1. Right click on Project in Eclipse
  2. Click on Properties
  3. Click on Project Facets Tab
  4. Change value from 3.1 to 3.0 for Dynamic Web Module as mentioned in below image.

Eclipse Project facets - Dynamic Web Module

Did it fix my problem? Unfortunately No

I was not able to apply setting as Apply and OK button was grayed out with error msg: Cannot change version of project facet Dynamic Web Module to 3.0.

I was literally stuck at this point, then How did I fix this issue?


  • Go to your Eclipse Workspace location
  • If you don’t find location then
    • Right click on project
    • Click on Resource
    • Go to your Location

Find Workspace Resource Properties - Crunchify Workspace


Go to location and open file <workspace>/.settings/org.eclipse.wst.common.project.facet.core.xml.

Find Eclipse org.eclipse.wst.common.project.facet.core.xml Path


Modify version for jst.web property to 3.0 from 3.1 and save file.


  • Refresh project
    • Right click on Project
    • Refresh (F5)
  • Clean project
    • Click on Project
    • Select Clean
  • Again
    • Right-click on project name
    • Click on Maven
    • Update project
  • Now checkout Project Facets screen again and error should be gone for you.

There will not be any error for Dynamic Web Module - Crunchify


Unistall Postgres sql

To remove postgres find the root postgres directory normally like


run : uninstall-postgresql

will remain the data folder and you have to remove manually.

start new installation (change your version/folder number):

sudo /Library/PostgreSQL/10/bin/pg_ctl -D  /Library/PostgreSQL/10/data start

stop postgres:

sudo /Library/PostgreSQL/10/bin/pg_ctl -D  /Library/PostgreSQL/10/data stop


Expand linux centos7 partition

from here very easy


1. Shut down the VM from Hypervisor


2. Expand the disk capacity from settings with your desired value. Here we choose to expand the VHD with additional 60 GB space.

3. Start the VM from the hypervisor.

4. Login to virtual machine console as root.

5. Execute below command to check the disk space.

fdisk -l

6. Now execute this below command to initialize the expanded space and mount it.

fdisk /dev/sda

WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').

7. After this enter ‘n’ in the next line for creating new partition.

Command action
e extended
p primary partition (1-4)

8. Then assign the partition number you wish based on your existing partition numbering.

Partition number (1-4): 3

Partition number (1-4): 3
Hex code (type L to list codes): 8e
Changed system type of partition 3 to 8e (Linux LVM)

9. In the next line choose code ‘8e’ for select the LINUX OS

Hex code (type L to list codes): 8e

Hex code (type L to list codes): 8e
Changed system type of partition 3 to 8e (Linux LVM)

10. Next enter ‘w’ to proceed further.

Command (m for help): w

Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.

11. Reboot the system.

12. Now we need to create physical & logical volumes execute below command to create physical volume.

pvcreate /dev/sda3

13. Execute below command to get the name of current Volume Group


14. Execute below command to extend the Volume Group with /dev/sda3

vgextend VolGroup /dev/sda3

15. Execute below command to get Logical Volume path.


16. Execute below command to extend the Logical Volume with /dev/sda3

lvextend /dev/VolGroup/lv_root /dev/sda3

17. Execute below command to update the Logical Volume

xfs_growfs /dev/VolGroup/lv_root

18. Check for the new disk space.

>df -h

19. Your Disk space is now successfully increased with 60 GB.

How to know if a disk is an SSD or an HDD Linux Centos 7

I needed to do this on the VPS and none of the provided solutions worked for me,

this answer did the trick

so, it is about reading random data from the drive and assessing the time.

time for i in `seq 1 1000`; do
    dd bs=4k if=/dev/sda count=1 skip=$(( $RANDOM * 128 )) >/dev/null 2>&1;

here are my results for SSD

real    0m1.375s
user    0m0.285s
sys     0m0.944s

and HDD

real    0m14.249s
user    0m0.752s
sys     0m6.284s