You seem to want a correlated subquery:
update table1 t1 set col2 = (select . . . from . . . where . . . ? = t1.col1 -- your condition goes here . . . );

You can use a named block around the loops:
search: { for (Type type : types) { for (Type t : types2) { if (some condition) { // Do something and break... break search; } } } }