java - empty DB joincolumn after cascade insert in bidirectional relationship -

i have 2 classes connected bidirectional manytoone / onetomany relationship:

member in classa:

@onetomany(cascade = cascadetype.all, orphanremoval = true, mappedby = "classa") private list<classb> classblist = new arraylist<classb>(); 

member in classb:

@manytoone @joincolumn(name = "classa_id", referencedcolumnname = "id") private classa classa; 

when call classa.getclassblist().add(newclassb); new db entry classb created, db column classa_id remains null. of course entities defined in persistence.xml.

i appreciate help, maybe it's little detail.

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thanks bigguy class looks now:

@onetomany(cascade = cascadetype.all, orphanremoval = true) @joincolumn(name = "classa_id", referencedcolumnname = "id") private list<classb> classblist = new arraylist<classb>();   @manytoone private classa classa 

the annotation @joincolumn indicates entity owner of relationship.

in case, owner classb.

so, should use line create relationship:

newclassb.setclassa(classa); 

if want create relationships line

classa.getclassblist().add(newclassb); 

make classa owner of relationship (move @joincolumn classa).