solution

src/test/java/core/basesyntax/ArrayList.java

@@ -0,0 +1,95 @@
+package core.basesyntax;
+
+import core.basesyntax.ArrayListIndexOutOfBoundsException;
+import java.util.Arrays;
+import java.util.NoSuchElementException;
+
+public class ArrayList<E> {
+    private static final int DEFAULT_CAPACITY = 10;
+    private E[] elements;
+    private int size;
+
+    public ArrayList() {
+        elements = (E[]) new Object[DEFAULT_CAPACITY];
+        size = 0;
+    }
+
+    public void add(E value) {
+        ensureCapacity();
+        elements[size++] = value;
+    }
+
+    public void add(E value, int index) {
+        validateIndexForAdd(index);
+        ensureCapacity();
+        System.arraycopy(elements, index, elements, index + 1, size - index);
+        elements[index] = value;
+        size++;
+    }
+
+    public void addAll(ArrayList<E> list) {
+        if (list == null || list.isEmpty()) {
+            return;
+        }
+
+        for (int i = 0; i < list.size; i++) {
+            add(list.get(i));
+        }
+    }
+
+    public E remove(int index) {
+        validateIndex(index);
+        E removedElement = elements[index];
+        System.arraycopy(elements, index + 1, elements, index, size - index - 1);
+        elements[--size] = null;
+
+        return removedElement;
+    }
+
+    public E remove(E value) {
+        for (int i = 0; i < size; i++) {
+            if ((value == null && elements[i] == null) || (value != null && value.equals(elements[i]))) {
+                return remove(i);
+            }
+        }
+
+        throw new NoSuchElementException("Element not found: " + value);
+    }
+
+    public E get(int index) {
+        validateIndex(index);
+
+        return elements[index];
+    }
+
+    public void set(E value, int index) {
+        validateIndex(index);
+        elements[index] = value;
+    }
+
+    public int size() {
+        return size;
+    }
+
+    public boolean isEmpty() {
+        return size == 0;
+    }
+
+    private void ensureCapacity() {
+        if (size == elements.length) {
+            elements = Arrays.copyOf(elements, elements.length * 2);
+        }
+    }
+
+    private void validateIndex(int index) {
+        if (index < 0 || index >= size) {
+            throw new ArrayListIndexOutOfBoundsException("Index out of bounds: " + index);
+        }
+    }
+
+    private void validateIndexForAdd(int index) {
+        if (index < 0 || index > size) {
+            throw new ArrayListIndexOutOfBoundsException("Index out of bounds for add: " + index);
+        }
+    }
+}

src/test/java/core/basesyntax/ArrayListIndexOutOfBoundsException.java

@@ -0,0 +1,7 @@
+package core.basesyntax;
+
+public class ArrayListIndexOutOfBoundsException extends RuntimeException {
+    public ArrayListIndexOutOfBoundsException(String message) {
+        super(message);
+    }
+}