Count number of entries in filtered table

(for this post some formulas and menu names are in spanish as my excel and computer are in spanish and excel formulas depend on this).

full list

The formula is:


The first two parameters are for the function itself. The important one is J:J which marks the column to count. What’s important here is this is not going to count filtered items in tables.

Watch out with headers! If you have headers in your table, add -1 to your formula.

Find differences for big dynamic lists in Excel

(for this post some formulas and menu names are in spanish as my excel and computer are in spanish and excel formulas depend on this).

Here is how to find and mark differences in unequal, really long lists or tables in Excel. For my example, one list is a partial list from other. Some items are missing and you’ve to find which ones are.

This is the full list.

full list

Read More

OAuth 2.0

Authentication process of verifying an identity. We confirm they’re who they say they are. (username & pwd).

Authorization process of verifying what someone is allowed to do. (Permissions and access control).

Past solutions

From worst one to best one and the problems they originate:

Credential Sharing

The worst one. An App is not able to differentiate between real user access and programmatical access.
Permissions are typically too broad. It also the ability to access more content than it should.

We could redirect the user off to the API where they could enter their credentials and get a cookie. This allows an app to access the API.

Dangerous because CSRF attacks. We’ve authorised the whole browser and not the app.

Read More

How to solve VirtualBox disk has run out of space


How to solve the problem “Low disk space on ‘Filesystem root’. The volume has only xMB disk space remaining” when you completely fill a virtual disk in VirtualBox.

(You have to delete all your snapshots first)

Open a cmd terminal and run the following command:

"c:\Program Files\Oracle\VirtualBox\VBoxManage.exe" modifymedium  
"c:\Users\mario\VirtualBox VMs\Ubuntu OTAN\Ubuntu OTAN.vdi" --resize 30000

The first path is an executable included with VirtualBox.
The second one is where your VDI actually is. --resize takes the size in MBs.

Open gpartitioner and resize it.

SCRUM PSM1 Certification - Index


Status: Certified!

This notes are my watered-down, personal version of The Scrum Guide 2020 and the following Udemy Course: “Preparation For Professional Scrum Master Level 1 (PSM1)” by Vladimir Raykov.

If you want to get ready for the certification exam, I fully recommend buying and watching his course, several times, in Udemy.

Scrum Guide 2020
1. Scrum Guide 2020 Notes
2. Scrum Glossary

“Preparation For Professional Scrum Master Level 1 (PSM1)” by Vladimir Raykov
1. Scrum Introduction
2. The Scrum Team
3. Scrum Events
4. Scrum Artifacts
5. Scrum Practices and Charts
6. A few words before the Exam
7. Recap of key concepts
8. Possible exam questions

Java Knowledge

This are my Java-related notes. Here I have all the knowledge I refer to when I have doubts about how to use or how to implement a framework / feature I’ve already implemented once.

Version changes

Interesting changes, new functionality and APIs that come to Java with each new version. They don’t include the full changes but the ones I deemed most useful or most interesting.

1. From Java 8 to Java 11
2. Java12
3. Java13


Small, functional snipets on how to implement a determined feature.

4. Java experience sheet
5. How to create a database intermediate table
6. Java date time API
7. New script files in Java


How to use and implement determined frameworks in a Java project (using Maven).

8. Spring in Action (Book)
9. Spring Cache
10. Spring Beans
11. Thymeleaf
12. Spring Cors

13. Maven (builder)
14. Testing (JUnit, TestNG, Mockito)
15. Vert.x (microservices)
16. Lombok (builder)
17. MapStruct (mapper)
18. Liquibase (database version control)