Merging two arrayLists into a new arrayList, with no duplicates and in order, in Java

Question

I am trying to \"combine\" two arrayLists, producing a new arrayList that contains all the numbers in the two combined arrayLists, but without any duplicate elements and the

Answer 1

Add elements in first arraylist

ArrayList firstArrayList = new ArrayList();

firstArrayList.add("A");
firstArrayList.add("B");
firstArrayList.add("C");
firstArrayList.add("D");
firstArrayList.add("E");

Add elements in second arraylist

ArrayList secondArrayList = new ArrayList();

secondArrayList.add("B");
secondArrayList.add("D");
secondArrayList.add("F");
secondArrayList.add("G");

Add first arraylist's elements in second arraylist

secondArrayList.addAll(firstArrayList);

Assign new combine arraylist and add all elements from both arraylists

ArrayList comboArrayList = new ArrayList(firstArrayList);
comboArrayList.addAll(secondArrayList);

Assign new Set for remove duplicate entries from arraylist

Set setList = new LinkedHashSet(comboArrayList);
comboArrayList.clear();
comboArrayList.addAll(setList);

Sorting arraylist

Collections.sort(comboArrayList);

Output

 A
 B
 C
 D
 E
 F
 G