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hellokoding / hellokoding-courses

HelloKoding provides practical coding guides series of Spring Boot, Java, Algorithms, and other topics on software engineering
https://hellokoding.com
MIT License
707 stars 2.17k forks source link

I'm getting a NPE at this point #3

Closed AndreGuima closed 5 years ago

AndreGuima commented 5 years ago

https://github.com/hellokoding/hellokoding-courses/blob/0cda5349ce56fb7c844c5a0d303713f82b6c1ed4/jpa-hibernate-examples/jpa-hibernate-many-to-many-mysql/src/main/java/com/hellokoding/jpa/book/Book.java#L31

AndreGuima commented 5 years ago

It was my mistake, sorry. I forgot to create a instance " = new HashSet<>();"