Task: Set
Java: import java.util.Arrays;
import java.util.Collections;
import java.util.Set;
import java.util.TreeSet;

public class Sets {
    public static void main(String[] args){
        Set<Integer> a = new TreeSet<>();
        
        
        
        
        
        Set<Integer> b = new TreeSet<>();
        Set<Integer> c = new TreeSet<>();
        Set<Integer> d = new TreeSet<>();
        
        a.addAll(Arrays.asList(1, 2, 3, 4, 5));
        b.addAll(Arrays.asList(2, 3, 4, 5, 6, 8));
        c.addAll(Arrays.asList(2, 3, 4));
        d.addAll(Arrays.asList(2, 3, 4));
        System.out.println("a: " + a);
        System.out.println("b: " + b);
        System.out.println("c: " + c);
        System.out.println("d: " + d);
        
        System.out.println("2 in a: " + a.contains(2));
        System.out.println("6 in a: " + a.contains(6));
        
        Set<Integer> ab = new TreeSet<>();
        ab.addAll(a);
        ab.addAll(b);
        System.out.println("a union b: " + ab);
        
        Set<Integer> a_b = new TreeSet<>();
        a_b.addAll(a);
        a_b.removeAll(b);
        System.out.println("a - b: " + a_b);
        
        System.out.println("c subset of a: " + a.containsAll(c));
        
        
        System.out.println("c = d: " + c.equals(d));
        System.out.println("d = c: " + d.equals(c));
        
        Set<Integer> aib = new TreeSet<>();
        aib.addAll(a);
        aib.retainAll(b);
        System.out.println("a intersect b: " + aib);
        
        System.out.println("add 7 to a: " + a.add(7));
        System.out.println("add 2 to a again: " + a.add(2));
        
        
        Set<Integer> empty = Collections.EMPTY_SET; 
        
        empty.isEmpty(); 
        empty.size();
        Collections.disjoint(a, b); 
        Collections.unmodifiableSet(a); 
    }
}

VB: 





Private Function createSet(t As Variant) As Collection
    Dim x As New Collection
    For Each elem In t
        x.Add elem, elem
    Next elem
    Set createSet = x
End Function
Private Function isElement(s As Variant, x As Collection) As Boolean
    Dim errno As Integer, t As Variant
    On Error GoTo err
    t = x(s)
    isElement = True
    Exit Function
err:
    isElement = False
End Function
Private Function setUnion(A As Collection, B As Collection) As Collection
    Dim x As New Collection
    For Each elem In A
        x.Add elem, elem
    Next elem
    For Each elem In B
        On Error Resume Next 
        x.Add elem, elem
    Next elem
    Set setUnion = x
End Function
Private Function intersection(A As Collection, B As Collection) As Collection
    Dim x As New Collection
    For Each elem In A
        If isElement(elem, B) Then x.Add elem, elem
    Next elem
    For Each elem In B
        If isElement(elem, A) Then
            On Error Resume Next
            x.Add elem, elem
        End If
    Next elem
    Set intersection = x
End Function
Private Function difference(A As Collection, B As Collection) As Collection
    Dim x As New Collection
    For Each elem In A
        If Not isElement(elem, B) Then x.Add elem, elem
    Next elem
    Set difference = x
End Function
Private Function subset(A As Collection, B As Collection) As Boolean
    Dim flag As Boolean
    flag = True
    For Each elem In A
        If Not isElement(elem, B) Then
            flag = False
            Exit For
        End If
    Next elem
    subset = flag
End Function
Private Function equality(A As Collection, B As Collection) As Boolean
    Dim flag As Boolean
    flag = True
    If A.Count = B.Count Then
        For Each elem In A
            If Not isElement(elem, B) Then
                flag = False
                Exit For
            End If
        Next elem
    Else
        flag = False
    End If
    equality = flag
End Function
Private Function properSubset(A As Collection, B As Collection) As Boolean
    Dim flag As Boolean
    flag = True
    If A.Count < B.Count Then
        For Each elem In A
            If Not isElement(elem, B) Then
                flag = False
                Exit For
            End If
        Next elem
    Else
        flag = False
    End If
    properSubset = flag
End Function
Public Sub main()
    
    Dim s As Variant
    Dim A As Collection, B As Collection, C As Collection
    s = [{"Apple","Banana","Pear","Pineapple"}]
    Set A = createSet(s) 
    
    Debug.Print isElement("Apple", A) 
    Debug.Print isElement("Fruit", A) 
    
    s = [{"Fruit","Banana","Pear","Orange"}]
    Set B = createSet(s)
    Set C = setUnion(A, B)
    
    Set C = intersection(A, B)
    
    Set C = difference(A, B)
    
    Debug.Print subset(A, B)
    
    Debug.Print equality(A, B)
    
    Debug.Print properSubset(A, B)
    
    A.Remove "Apple"
    
    A.Remove 1
    
    A.Add "10", "10"
End Sub