You cannot resize an array in java.

Once the size of array is declared, it remains fixed.

Instead you can use ArrayList that has dynamic size, meaning you don't need to worry about its size. If your array list is not big enough to accommodate new values then it will be resized automatically.

ArrayList<String> ar = new ArrayList<String>();
String s1 ="Test1";
String s2 ="Test2";
String s3 ="Test3";
ar.add(s1);
ar.add(s2);
ar.add(s3);

String s4 ="Test4";
ar.add(s4);

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 array
for( String oneItem : where ) {
    ...
}

// get specific items
where.get( 1 );

Arrays in Java have a defined size, you cannot change it later by adding or removing elements (you can read some basics here).

Instead, use a List:

ArrayList<String> mylist = new ArrayList<String>();
mylist.add(mystring); //this adds an element to the list.

Of course, if you know beforehand how many strings you are going to put in your array, you can create an array of that size and set the elements by using the correct position:

String[] myarray = new String[numberofstrings];
myarray[23] = string24; //this sets the 24'th (first index is 0) element to string24.

From 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. You've seen an example of arrays already, in the main method of the "Hello World!" application. This section discusses arrays in greater detail.

So in the case of a String array, once you create it with some length, you can't modify it, but you can add elements until you fill it.

String[] arr = new String[10]; // 10 is the length of the array.
arr[0] = "kk";
arr[1] = "pp";
...

So if your requirement is to add many objects, it's recommended that you use Lists like:

List<String> a = new ArrayList<String>();
a.add("kk");
a.add("pp"); 

You already have built-in method for that: -

List<String> species = Arrays.asList(speciesArr);

NOTE: - You should use List<String> species not ArrayList<String> species.

Arrays.asList returns a different ArrayList -> java.util.Arrays.ArrayList which cannot be typecasted to java.util.ArrayList.

Then you would have to use addAll method, which is not so good. So just use List<String>

NOTE: - The list returned by Arrays.asList is a fixed size list. If you want to add something to the list, you would need to create another list, and use addAll to add elements to it. So, then you would better go with the 2nd way as below: -

    String[] arr = new String[1];
    arr[0] = "rohit";
    List<String> newList = Arrays.asList(arr);

    // Will throw `UnsupportedOperationException
    // newList.add("jain"); // Can't do this.

    ArrayList<String> updatableList = new ArrayList<String>();

    updatableList.addAll(newList); 

    updatableList.add("jain"); // OK this is fine. 

    System.out.println(newList);       // Prints [rohit]
    System.out.println(updatableList); //Prints [rohit, jain]