First stage: Array was replaced with ArrayList

SetArtilleriesGeneric.java

@@ -1,12 +1,18 @@
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.Objects;
+
 public class SetArtilleriesGeneric<T> {
-    private final Object[] _places;
+    private final ArrayList<T> _places;
+    private final int _maxCount;
 
     public int getCount() {
-        return _places.length;
+        return _places.size();
     }
 
     public SetArtilleriesGeneric(int count) {
-        _places = new Object[count];
+        _maxCount = count;
+        _places = new ArrayList<>(count);
     }
 
     public int insert(T artillery) {
@@ -14,57 +20,37 @@ public class SetArtilleriesGeneric<T> {
     }
 
     public int insert(T artillery, int position) {
-        if (position < 0 || position >= getCount()) {
+        if (position < 0 || position >= getCount() || getCount() == _maxCount) {
             return -1;
         }
 
-        if (_places[position] == null) {
+        _places.add(position, artillery);
-            _places[position] = artillery;
-            return position;
-        }
 
-        int firstNull = -1;
-
-        for (int i = position + 1; i < getCount(); i++)
-        {
-            if (_places[i] == null)
-            {
-                firstNull = i;
-                break;
-            }
-        }
-
-        if (firstNull == -1)
-        {
-            return -1;
-        }
-
-        System.arraycopy(_places, position, _places, position + 1, firstNull - position);
-
-        _places[position] = artillery;
         return position;
     }
 
-    @SuppressWarnings("unchecked")
     public T remove(int position) {
         if (position < 0 || position >= getCount())
         {
             return null;
         }
 
-        var result = _places[position];
+        T result = _places.get(position);
 
-        _places[position] = null;
+        _places.remove(position);
 
-        return (T) result;
+        return result;
     }
 
-    @SuppressWarnings("unchecked")
     public T get(int position) {
         if (position < 0 || position >= getCount()) {
             return null;
         }
 
-        return (T) _places[position];
+        return _places.get(position);
+    }
+
+    public Iterator<T> getArtilleries() {
+        return _places.stream().filter(Objects::nonNull).iterator();
     }
 }