Reversing an array is a classic problem often asked in Java interviews. In this tutorial, we'll reverse an array manually without using Collections.reverse() or Arrays utility classes.
🧮 Logic
We use two pointers: one starting from the beginning, and one from the end. Swap their values while moving toward the center.
✅ Java Program
public class ReverseArray {
public static void main(String[] args) {
int[] arr = {10, 20, 30, 40, 50};
System.out.println("Original Array:");
printArray(arr);
reverseArray(arr);
System.out.println("Reversed Array:");
printArray(arr);
}
static void reverseArray(int[] arr) {
int start = 0, end = arr.length - 1;
while (start < end) {
int temp = arr[start];
arr[start] = arr[end];
arr[end] = temp;
start++;
end--;
}
}
static void printArray(int[] arr) {
for (int num : arr) {
System.out.print(num + " ");
}
System.out.println();
}
}
🧠 Interview Tip
This question is often followed by variations like "reverse only even elements" or "reverse using recursion." Make sure to explain your swap logic clearly.
✅ Output
Original Array: 10 20 30 40 50 Reversed Array: 50 40 30 20 10
📌 Conclusion
We learned how to reverse an array in Java using simple loop logic and without relying on any built-in methods. This program builds your core understanding of arrays and data manipulation.
🔄 Master Array Traversal & Two-Pointer Techniques
Reversing an array is one of the most fundamental Java problems and a common starting point for mastering two-pointer and in-place algorithms. Strengthen your array problem-solving skills by exploring these closely related Java programs and interview resources.
🧠 Java Coding Round Questions
Practice array-based logic problems frequently asked in coding rounds.
✅ Check if Array Is Sorted
Learn how traversal logic is reused in array order validation.
🚫 Remove Duplicates from Array
Understand how reversed or sorted arrays affect duplicate removal strategies.
🔍 Find Duplicates in Array
Practice scanning arrays using efficient traversal techniques.
🥈 Second Largest Element in Array
Apply traversal logic to find constrained values in arrays.
📊 Sort Array Without Built-ins
Learn sorting techniques often combined with array reversal.
📦 Java Collections Interview Questions
Understand differences between arrays and collection traversal.
🎯 Java Interview Questions (Freshers)
Common interview questions involving arrays and traversal logic.
🧪 Advanced Java Programs (Real-World)
Apply array manipulation logic in real-world Java scenarios.