f()
{   Collection list = new LinkedList();
    //...
    g( list );
}

g( Collection list )
{
    list.add( ... );
    g2( list )
}

f()
{   Collection c = new HashSet();
    //...
    g( c );
}

g( Collection c )
{
    for( Iterator i = c.iterator(); i.hasNext() )
        do_something_with( i.next() );
}

f2()
{   Collection c = new HashSet();
    //...
    g2( c.iterator() );
}

g2( Iterator i )
{   while( i.hasNext() )
        do_something_with( i.next() );
}

class Stack extends ArrayList
{   private int stack_pointer = 0;

    public void push( Object article )
    {   add( stack_pointer++, article );
    }

    public Object pop()
    {   return remove( --stack_pointer );
    }

    public void push_many( Object[] articles )
    {   for( int i = 0; i < articles.length; ++i )
            push( articles[i] );
    }
}

Stack a_stack = new Stack();
a_stack.push("1");
a_stack.push("2");
a_stack.clear();

class Stack
{
    private int stack_pointer = 0;
    private ArrayList the_data = new ArrayList();
    
    public void push( Object article )
{
    the_data.add( stack_poniter++, article );
}

public Object pop()
{
    return the_data.remove( --stack_pointer );
}

public void push_many( Object[] articles )
{
    for£¨ int i = 0; i < o.length; ++i £©
        push( articles[i] );
}
}

class Monitorable_stack extends Stack
{
    private int high_water_mark = 0;
    private int current_size;

    public void push( Object article )
    {
        if( ++current_size > high_water_mark )
            high_water_mark = current_size;
        super.push( article );
    }

    publish Object pop()
    {
        --current_size;
        return super.pop();
    }

    public int maximum_size_so_far()
    {
        return high_water_mark;
    }
}