26thAirhacksQ&A.md

26thAirhacksQ&A.md

Ask questions and see you at May, 9th at 6.PM. CET: http://www.ustream.tv/channel/adambien Also see archives: airhacks.tv

1. Java EE 8 News

Hi Adam,

How would you tackle from the performance perspective the traversing of JPA relationships.
Here is an example:

Class RiskAssessment{
        ...
        List<Step> steps; // one-to-many
}

Class Step{
        ...
        List<HazardType > hazardTypes; // one-to-many
}

Class HazardType{
        ...
        List<Hazard> hazards; // one-to-many
}

Class Hazard{
        ...
        List<Control> controls; // one-to-many
}

Given a RiskAssessment id, I'd like to load all the Hazard and Control objects associated with it.

List<Hazard> loadAllHazardsAndControls(Integer riskAssessmentId){
......
}

I'd like to access the DB as few times as possible.I know that using nested to loops is not efficient as I would fall into the N+1 query issue.

How would you tackle this problem? Using JPQL queries and chaching query_results? If a second call to the method loadAllHazardsAndControls() occurs with the same Id parameter I would like my query(or my way to load the relationships) to remain completely In Memory.

Thanks in advance!

Hi Adam Bien,

I want to Develop Java EE Website, with multi-language(Arabic and English) with JSF.

Arabic is read right to left, layout, fonts are different.
Do i have to maintain two different websites, one for Arabic and the second for English ?
http://www.mydomain.com/ar
http://www.mydomain.com/en

Thanks in advance