add string to String array

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);