From e383b94e1b44a6f778f17a3fa805b454498609c2 Mon Sep 17 00:00:00 2001
From: Alexey Andreev <konsoletyper@gmail.com>
Date: Mon, 25 Sep 2023 15:23:18 +0200
Subject: [PATCH] classlib: fix implementations of SequencedCollection methods
 in ArrayList

---
 .../teavm/classlib/java/util/TArrayList.java  | 15 +++++++--
 .../classlib/java/util/ArrayListTest.java     | 32 +++++++++++++++++++
 2 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/classlib/src/main/java/org/teavm/classlib/java/util/TArrayList.java b/classlib/src/main/java/org/teavm/classlib/java/util/TArrayList.java
index d7c47cae0..0cfed0e56 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/util/TArrayList.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/util/TArrayList.java
@@ -16,6 +16,7 @@
 package org.teavm.classlib.java.util;
 
 import java.util.Arrays;
+import java.util.NoSuchElementException;
 import java.util.Objects;
 import java.util.function.Consumer;
 import org.teavm.classlib.java.io.TSerializable;
@@ -66,12 +67,14 @@ public class TArrayList<E> extends TAbstractList<E> implements TCloneable, TSeri
 
     @Override
     public E getFirst() {
-        return get(0);
+        checkIfNotEmpty();
+        return array[0];
     }
 
     @Override
     public E getLast() {
-        return get(size - 1);
+        checkIfNotEmpty();
+        return array[size - 1];
     }
 
     @Override
@@ -124,14 +127,22 @@ public class TArrayList<E> extends TAbstractList<E> implements TCloneable, TSeri
 
     @Override
     public E removeFirst() {
+        checkIfNotEmpty();
         return remove(0);
     }
 
     @Override
     public E removeLast() {
+        checkIfNotEmpty();
         return remove(size - 1);
     }
 
+    private void checkIfNotEmpty() {
+        if (isEmpty()) {
+            throw new NoSuchElementException();
+        }
+    }
+
     @Override
     public E remove(int index) {
         checkIndex(index);
diff --git a/tests/src/test/java/org/teavm/classlib/java/util/ArrayListTest.java b/tests/src/test/java/org/teavm/classlib/java/util/ArrayListTest.java
index 5373ad02e..25f1eb4dd 100644
--- a/tests/src/test/java/org/teavm/classlib/java/util/ArrayListTest.java
+++ b/tests/src/test/java/org/teavm/classlib/java/util/ArrayListTest.java
@@ -29,6 +29,7 @@ import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.ListIterator;
+import java.util.NoSuchElementException;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.teavm.junit.TeaVMTestRunner;
@@ -290,4 +291,35 @@ public class ArrayListTest {
         lit.add("x");
         assertEquals(List.of("d", "x", "a"), list);
     }
+
+    @Test
+    public void sequenceCollectionMethodsOnEmpty() {
+        var empty = new ArrayList<>();
+
+        try {
+            empty.getFirst();
+            fail();
+        } catch (NoSuchElementException e) {
+            // ok
+        }
+        try {
+            empty.getLast();
+            fail();
+        } catch (NoSuchElementException e) {
+            // ok
+        }
+
+        try {
+            empty.removeFirst();
+            fail();
+        } catch (NoSuchElementException e) {
+            // ok
+        }
+        try {
+            empty.removeLast();
+            fail();
+        } catch (NoSuchElementException e) {
+            // ok
+        }
+    }
 }