Gil Brandao

https://github.com/jooby-project/jooby/blob/9481d17626bab1d5f31f85d26876e5843a81e320/jooby/src/main/java/io/jooby/ServerOptions.java#L484

The exempt tax belongs to the Portugal context, but the validation done verifies if the tax context is a subcontext of the given context. Being on the toplevel, the "PortugalContext".getParent()...

calling: ``` entrybuilder.setProduct(productUID=null) ``` raises: ``` java.lang.NullPointerException: The field field.product can not be null at org.apache.commons.lang3.Validate.notNull(Validate.java:222) at com.premiumminds.billy.core.util.BillyValidator.notNull(BillyValidator.java:88) ``` while calling entrybuilder.build() without having called setProduct() raises: ``` java.lang.NullPointerException at...