How to add new elements to an array?

The size of an array can't be modified. If you want a bigger array you have to instantiate a new one.

A better solution would be to use an ArrayList which can grow as you need it. The method ArrayList.toArray( T[] a ) gives you back your array if you need it in this form.

List<String> where = new ArrayList<String>();where.add( ContactsContract.Contacts.HAS_PHONE_NUMBER+"=1" );where.add( ContactsContract.Contacts.IN_VISIBLE_GROUP+"=1" );

If you need to convert it to a simple array...

String[] simpleArray = new String[ where.size() ];where.toArray( simpleArray );

But most things you do with an array you can do with this ArrayList, too:

// iterate over the arrayfor( String oneItem : where ) {    ...}// get specific itemswhere.get( 1 );

Use a List<String>, such as an ArrayList<String>. It's dynamically growable, unlike arrays (see: Effective Java 2nd Edition, Item 25: Prefer lists to arrays).

import java.util.*;//....List<String> list = new ArrayList<String>();list.add("1");list.add("2");list.add("3");System.out.println(list); // prints "[1, 2, 3]"

If you insist on using arrays, you can use java.util.Arrays.copyOf to allocate a bigger array to accomodate the additional element. This is really not the best solution, though.

static <T> T[] append(T[] arr, T element) {    final int N = arr.length;    arr = Arrays.copyOf(arr, N + 1);    arr[N] = element;    return arr;}String[] arr = { "1", "2", "3" };System.out.println(Arrays.toString(arr)); // prints "[1, 2, 3]"arr = append(arr, "4");System.out.println(Arrays.toString(arr)); // prints "[1, 2, 3, 4]"

This is O(N) per append. ArrayList, on the other hand, has O(1) amortized cost per operation.

See also

• Java Tutorials/Arrays
  • An array is a container object that holds a fixed number of values of a single type. The length of an array is established when the array is created. After creation, its length is fixed.
• Java Tutorials/The List interface

Apache Commons Lang has

T[] t = ArrayUtils.add( initialArray, newitem );

it returns a new array, but if you're really working with arrays for some reason, this may be the ideal way to do this.