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Loops are one of the most powerful tools in programming, and in Java, they help you repeat actions without writing the same line of code over and over again. One of the most common and useful loop types is the for loop.
In this guide, we’ll focus on the Java for statement—what it is, how it works, and how you can use it in real-world situations. Whether you're printing a list of numbers or processing items in an array, the for loop is your go-to tool.
Let’s get started!

What Is a For Loop?

A for loop in Java allows you to run a block of code a specific number of times. It’s great when you know in advance how many times you want the loop to repeat.
The basic structure looks like this: 
for (initialization; condition; update) {
    // code to run each time the loop repeats
}

Breakdown:

  • Initialization: Set a starting point (e.g., int i = 0)
  • Condition: The loop runs as long as this is true (e.g., i < 5)
  • Update: Runs after each loop cycle (e.g., i++)

A Simple For Loop Example

Let’s print numbers from 1 to 5: 
for (int i = 1; i <= 5; i++) {
    System.out.println("Number: " + i);
}

What happens here:

  • The loop starts with i = 1
  • It checks if i <= 5
  • If true, it runs the code block and then increases i by 1
  • This repeats until i is greater than 5
Output: 
Number: 1
Number: 2
Number: 3
Number: 4
Number: 5

When to Use a For Loop

Use a for loop when:
  • You know how many times you want to run something
  • You're working with arrays or collections where you're looping from start to finish
  • You want compact, readable control over loop variables

Looping in Reverse

Want to count down instead of up? Just change the loop values: 
for (int i = 5; i >= 1; i--) {
    System.out.println("Countdown: " + i);
}
This loop decreases i each time instead of increasing it.

Using For Loops with Arrays

For loops are perfect for going through arrays.
Example: 
String[] fruits = {"Apple", "Banana", "Cherry"};

for (int i = 0; i < fruits.length; i++) {
    System.out.println(fruits[i]);
}
Output: 
Apple
Banana
Cherry
Here, fruits.length tells the loop how many times to run.

Enhanced For Loop (For-Each)

Java also offers a simpler version of the for loop for arrays and collections: 
for (String fruit : fruits) {
    System.out.println(fruit);
}
This is called the enhanced for loop or for-each loop. It’s cleaner and safer when you don’t need to know the index.
Use this when:
  • You just want to go through every item in an array or list
  • You don’t need to modify the array or access items by index

Common Mistakes to Avoid

1. Infinite Loops

If you forget to update the loop variable, the loop might never stop: 
for (int i = 0; i < 10;) {
    System.out.println("Oops!");
    // Missing i++ here
}
This will print "Oops!" forever (or until your program crashes).

2. Off-by-One Errors

Make sure your loop boundaries are correct. For example: 
for (int i = 0; i <= 5; i++) { ... } // Runs 6 times
for (int i = 0; i < 5; i++) { ... }  // Runs 5 times

Nested For Loops

You can put one for loop inside another. This is useful for working with grids, tables, or combinations.
Example: 
for (int i = 1; i <= 3; i++) {
    for (int j = 1; j <= 2; j++) {
        System.out.println("i = " + i + ", j = " + j);
    }
}
Output: 
i = 1, j = 1
i = 1, j = 2
i = 2, j = 1
i = 2, j = 2
i = 3, j = 1
i = 3, j = 2

Tips for Writing Better For Loops

  • Use meaningful variable names when looping over data. Instead of i, try index or count when appropriate.
  • Keep your loop condition simple and easy to read.
  • Avoid modifying the loop variable inside the loop body unless you know what you’re doing.
  • If you're using loops with collections (like ArrayList), consider using the enhanced for loop for better readability.

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