From fdd485ddd91a42ba07ae33e6f94bee8a6ea1e507 Mon Sep 17 00:00:00 2001
From: Ahmed Tawila <atawila@yahoo.com>
Date: Sun, 22 Oct 2017 10:48:39 +0200
Subject: [PATCH] BAEL-1250 Initializing Arrays in Java

---
 .../com/baeldung/array/ArrayInitializer.java  | 48 +++++++++++++++++++
 .../baeldung/array/ArrayInitializerTest.java  | 48 +++++++++++++++++++
 2 files changed, 96 insertions(+)
 create mode 100644 core-java/src/main/java/com/baeldung/array/ArrayInitializer.java
 create mode 100644 core-java/src/test/java/com/baeldung/array/ArrayInitializerTest.java

diff --git a/core-java/src/main/java/com/baeldung/array/ArrayInitializer.java b/core-java/src/main/java/com/baeldung/array/ArrayInitializer.java
new file mode 100644
index 0000000000..0c9bf1834e
--- /dev/null
+++ b/core-java/src/main/java/com/baeldung/array/ArrayInitializer.java
@@ -0,0 +1,48 @@
+package com.baeldung.array;
+
+import java.util.Arrays;
+
+public class ArrayInitializer {
+
+    public static int[] initializeArrayInLoop() {
+        int array[] = new int[5];
+        for (int i = 0; i < array.length; i++)
+            array[i] = i + 2;
+        return array;
+    }
+
+    public static int[][] initializeMultiDimensionalArrayInLoop() {
+        int array[][] = new int[2][5];
+        for (int i = 0; i < 2; i++)
+            for (int j = 0; j < 5; j++)
+                array[i][j] = j + 1;
+        return array;
+    }
+
+    public static String[] initializeArrayAtTimeOfDeclarationMethod1() {
+        String array[] = new String[] { "Toyota", "Mercedes", "BMW", "Volkswagen", "Skoda" };
+        return array;
+    }
+
+    public static int[] initializeArrayAtTimeOfDeclarationMethod2() {
+        int[] array = new int[] { 1, 2, 3, 4, 5 };
+        return array;
+    }
+
+    public static int[] initializeArrayAtTimeOfDeclarationMethod3() {
+        int array[] = { 1, 2, 3, 4, 5 };
+        return array;
+    }
+
+    public static long[] initializeArrayUsingArraysFill() {
+        long array[] = new long[5];
+        Arrays.fill(array, 30);
+        return array;
+    }
+
+    public static int[] initializeArrayRangeUsingArraysFill() {
+        int array[] = new int[5];
+        Arrays.fill(array, 0, 3, -50);
+        return array;
+    }
+}
diff --git a/core-java/src/test/java/com/baeldung/array/ArrayInitializerTest.java b/core-java/src/test/java/com/baeldung/array/ArrayInitializerTest.java
new file mode 100644
index 0000000000..0797a524c4
--- /dev/null
+++ b/core-java/src/test/java/com/baeldung/array/ArrayInitializerTest.java
@@ -0,0 +1,48 @@
+package com.baeldung.array;
+
+import static com.baeldung.array.ArrayInitializer.initializeArrayAtTimeOfDeclarationMethod1;
+import static com.baeldung.array.ArrayInitializer.initializeArrayAtTimeOfDeclarationMethod2;
+import static com.baeldung.array.ArrayInitializer.initializeArrayAtTimeOfDeclarationMethod3;
+import static com.baeldung.array.ArrayInitializer.initializeArrayInLoop;
+import static com.baeldung.array.ArrayInitializer.initializeArrayRangeUsingArraysFill;
+import static com.baeldung.array.ArrayInitializer.initializeArrayUsingArraysFill;
+import static com.baeldung.array.ArrayInitializer.initializeMultiDimensionalArrayInLoop;
+import static org.junit.Assert.assertArrayEquals;
+
+import org.junit.Test;
+
+public class ArrayInitializerTest {
+
+    @Test
+    public void whenInitializeArrayInLoop_thenCorrect() {
+        assertArrayEquals(new int[] { 2, 3, 4, 5, 6 }, initializeArrayInLoop());
+    }
+
+    @Test
+    public void whenInitializeMultiDimensionalArrayInLoop_thenCorrect() {
+        assertArrayEquals(new int[][] { { 1, 2, 3, 4, 5 }, { 1, 2, 3, 4, 5 } }, initializeMultiDimensionalArrayInLoop());
+    }
+
+    @Test
+    public void whenInitializeArrayAtTimeOfDeclarationMethod1_thenCorrect() {
+        assertArrayEquals(new String[] { "Toyota", "Mercedes", "BMW", "Volkswagen", "Skoda" }, initializeArrayAtTimeOfDeclarationMethod1());
+    }
+
+    @Test
+    public void whenInitializeArrayAtTimeOfDeclarationMethod2_thenCorrect() {
+        assertArrayEquals(new int[] { 1, 2, 3, 4, 5 }, initializeArrayAtTimeOfDeclarationMethod2());
+    }
+
+    @Test
+    public void whenInitializeArrayAtTimeOfDeclarationMethod3_thenCorrect() {
+        assertArrayEquals(new int[] { 1, 2, 3, 4, 5 }, initializeArrayAtTimeOfDeclarationMethod3());
+    }
+
+    public void whenInitializeArrayUsingArraysFill_thenCorrect() {
+        assertArrayEquals(new long[] { 30, 30, 30, 30, 30 }, initializeArrayUsingArraysFill());
+    }
+
+    public void whenInitializeArrayRangeUsingArraysFill() {
+        assertArrayEquals(new int[] { -50, -50, -50, 0, 0 }, initializeArrayRangeUsingArraysFill());
+    }
+}