The purpose of the "camps" is explicit - to create the next generation of mujahadeen. The name of this year's camps are "youthfulness victory."
If there are children under 15 in these camps, then Islamic Jihad is violating international law by recruiting them. Not that "human rights" NGOs will say anything against it.
In other Islamic Jihad news, one of its military leaders now claims that their rockets can reach all parts of "Palestine."