how to combined three list and remove duplicates in java 8 code example

Example 1: compare two lists and remove duplicates java

listA.removeAll(new HashSet(listB));

Example 2: remove duplicates from list java

ArrayList<Object> withDuplicateValues;
 HashSet<Object> withUniqueValue = new HashSet<>(withDuplicateValues);
 
 withDuplicateValues.clear();
 withDuplicateValues.addAll(withUniqueValue);