Вот пример кода, который может вам помочь.
java.util.ArrayList al1 = [Your first array list retrieval method from first table];
java.util.ArrayList al2 = [Your second array list retrieval method from second table];
//Use iterator to go through each element of al1
java.util.Iterator iter1 = al1.iterator();
while(iter1.hasNext()){
//I assume strings are there in your array list
java.lang.String currentElement = iter1.next();
if (!al2.contains(currentElement)){
//Your code to insert into second table
}
}