Java™ Phrasebook

Resizing an Array

// use an ArrayList List myArray = new ArrayList();

In Java, regular arrays of objects or primitives can not be dynamically resized. If you want an array larger than what was originally declared, you’d have to declare a new larger array and copy the contents from the original array to the new larger array. Here we show how this is accomplished:

int[] tmp = new int[myArray.length + 10];
System.arraycopy(myArray, 0, tmp, 0,
myArray.length);
myArray = tmp;

In this example, we have an array of integers called myArray, and we want to expand the size of the array by 10 elements. We create a new array, which we call tmp, and initialize it to the length of myArray + 10. We then use the System.arrayCopy() method to copy the contents ...