Is the word joão the same in Brazilian and European Portuguese?

Yes

The word "João" is a proper noun (a name) and is identical in spelling, meaning, and grammatical function in both Brazilian and Continental Portuguese. The only difference lies in pronunciation. In Brazil, the nasal vowel "ão" is often pronounced with a more open sound, and the cadence of the word follows Brazilian prosody. In Portugal, the vowels may be more closed or reduced, and the accentuation follows the specific rhythmic patterns of European Portuguese.

Brazilian Portuguese Examples

1. O João é meu melhor amigo. (João is my best friend.)
2. Eu vou encontrar o João no shopping. (I am going to meet João at the mall.)
3. O João está trabalhando muito hoje. (João is working a lot today.)
4. Você viu o João na festa? (Did you see João at the party?)
5. O João gosta de comer pizza. (João likes to eat pizza.)

Continental Portuguese Examples

1. O João é o meu melhor amigo. (João is my best friend.)
2. Vou encontrar o João no centro comercial. (I am going to meet João at the shopping center.)
3. O João está a trabalhar muito hoje. (João is working a lot today.)
4. Já viste o João na festa? (Have you seen João at the party?)
5. O João gosta de comer pizza. (João likes to eat pizza.)