Top 10 Methods for Java Arrays

The following are top 10 methods for Java Array. They are the most voted questions from stackoverflow.

0. Declare an array

String[] aArray = new String[5];String[] bArray = {"a","b","c", "d", "e"};String[] cArray = new String[]{"a","b","c","d","e"};

1. Print an array in Java

int[] intArray = { 1, 2, 3, 4, 5 };String intArrayString = Arrays.toString(intArray); // print directly will print reference valueSystem.out.println(intArray);// [I@7150bd4d System.out.println(intArrayString);// [1, 2, 3, 4, 5]

2. Create an ArrayList from an array

String[] stringArray = { "a", "b", "c", "d", "e" };ArrayList<String> arrayList = new ArrayList<String>(Arrays.asList(stringArray));System.out.println(arrayList);// [a, b, c, d, e]

3. Check if an array contains a certain value

String[] stringArray = { "a", "b", "c", "d", "e" };boolean b = Arrays.asList(stringArray).contains("a");System.out.println(b);// true

4. Concatenate two arrays

int[] intArray = { 1, 2, 3, 4, 5 };int[] intArray2 = { 6, 7, 8, 9, 10 };// Apache Commons Lang libraryint[] combinedIntArray = ArrayUtils.addAll(intArray, intArray2);

5. Declare an array inline

method(new String[]{"a", "b", "c", "d", "e"});

6. Joins the elements of the provided array into a single String

// containing the provided list of elements// Apache common langString j = StringUtils.join(new String[] { "a", "b", "c" }, ", ");System.out.println(j);// a, b, c

7. Covnert an ArrayList to an array

String[] stringArray = { "a", "b", "c", "d", "e" };ArrayList<String> arrayList = new ArrayList<String>(Arrays.asList(stringArray));String[] stringArr = new String[arrayList.size()];arrayList.toArray(stringArr);for (String s : stringArr)System.out.println(s);

8. Convert an array to a set

Set<String> set = new HashSet<String>(Arrays.asList(stringArray));System.out.println(set);//[d, e, b, c, a]

9. Reverse an array

int[] intArray = { 1, 2, 3, 4, 5 };ArrayUtils.reverse(intArray);System.out.println(Arrays.toString(intArray));//[5, 4, 3, 2, 1]

10. Remove element of an array

int[] intArray = { 1, 2, 3, 4, 5 };int[] removed = ArrayUtils.removeElement(intArray, 3);//create a new arraySystem.out.println(Arrays.toString(removed));

One more – convert int to byte array

byte[] bytes = ByteBuffer.allocate(4).putInt(8).array(); for (byte t : bytes) {   System.out.format("0x%x ", t);}