How to Copy a Two-Dimensional Array in Java

What are the methods to copy a two-dimensional array in Java?

// Original array
int[][] sourceArray = {{1, 2, 3}, {4, 5, 6}};

// Creating a new array with the same dimensions
int[][] destinationArray = new int[sourceArray.length][sourceArray[0].length];

// Copying elements using nested loops
for (int i = 0; i < sourceArray.length; i++) {
    for (int j = 0; j < sourceArray[i].length; j++) {
        destinationArray[i][j] = sourceArray[i][j];
    }
}

Copying a two-dimensional array in Java can be achieved through various methods, including using loops, the Arrays.copyOf method, or the System.arraycopy method. Each method has its advantages depending on the use case.

// Using Arrays.copyOf for shallow copy
int[][] copiedArray = Arrays.copyOf(sourceArray, sourceArray.length);
for(int i = 0; i < copiedArray.length; i++) {
    copiedArray[i] = Arrays.copyOf(sourceArray[i], sourceArray[i].length);
}

Causes

• Understanding the need to clone or duplicate an array for data manipulation.
• Differences in shallow vs. deep copy concerns.

Solutions

• Using nested loops for manual copying of elements.
• Applying Arrays.copyOf for creating a shallow copy efficiently.
• Leveraging System.arraycopy for optimized performance.

Mistake: Forgetting to clone inner arrays, leading to a shallow copy.

Solution: Use a nested copy method to ensure all elements are duplicated.

Mistake: Not accounting for jagged (non-rectangular) arrays when using copy methods.

Solution: Check the length of each inner array before copying.