How Can I Resize a Java Array While Keeping Existing Elements?

Maintaining Current Elements While Resizing an Array in Java

When manipulating data structures, the need to resize arrays often arises while preserving the existing elements. While Java does not provide a direct method to resize arrays, several approaches can achieve this goal.

1. Array Manipulation

One technique involves creating a new array of the desired size and copying the existing elements from the original array using System.arraycopy(...). This process ensures the preservation of the original elements.

Code Example:

int[] originalArray = {1, 2, 3, 4, 5};
int[] resizedArray = new int[originalArray.length + 1];

System.arraycopy(originalArray, 0, resizedArray, 0, originalArray.length);

2. ArrayList Class

The java.util.ArrayList class offers a convenient way to dynamically grow an array. It automatically adjusts its size as new elements are added.

Code Example:

ArrayList<Integer> arrayList = new ArrayList<>();
arrayList.add(1);
arrayList.add(2);
arrayList.add(3);

3. Arrays.copyOf() Method

The java.util.Arrays.copyOf(...) methods provide another option for resizing arrays. It returns a new array containing the elements of the original array.

Code Example:

int[] originalArray = {1, 2, 3, 4, 5};
int[] resizedArray = Arrays.copyOf(originalArray, originalArray.length + 1);

Conclusion

While Java does not allow direct resizing of arrays, the techniques mentioned above can effectively accomplish this task while maintaining the existing elements. Choosing the appropriate approach depends on the specific requirements and performance considerations of the application.

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