1. For Loop in Java :

The for loop in Java is a control flow statement that allows you to execute a block of code repeatedly for a fixed number of times. It is commonly used when you know the exact number of iterations needed. The for loop consists of three parts: initialization, condition, and iteration expression.

Syntax:

for (initialization; condition; iterationExpression) {
// Block of code to be executed
}

• Initialization: This part initializes the loop control variable, typically a counter variable, and is executed only once at the beginning of the loop.
• Condition: This part specifies the condition that must be true for the loop to continue iterating. If the condition evaluates to false, the loop terminates.
• Iteration Expression: This part updates the loop control variable after each iteration, usually incrementing or decrementing its value.

Example:

// Print numbers from 1 to 5
for (int i = 1; i <= 5; i++) {
System.out.println("Number: " + i);
}

2. While Loop in Java :

The while loop in Java is a control flow statement that executes a block of code repeatedly as long as a specified condition is true. It is useful when the number of iterations is not known in advance and is determined by the evaluation of a condition. The while loop evaluates the condition before each iteration and continues execution as long as the condition remains true.

Syntax:

while (condition) {
// Block of code to be executed
}

Example:
Let’s consider an example where we use a while loop to print numbers from 1 to 5:

public class WhileLoopExample {
public static void main(String[] args) {
// Initialize the counter
int i = 1;

// Execute the loop as long as i is less than or equal to 5
while (i <= 5) {
System.out.println("Value of i: " + i);

// Increment the counter
i++;
}
}
}

3. do-while Loop in Java :

The do-while loop in Java is a control flow statement that executes a block of code at least once, and then repeats the execution as long as a specified condition is true. Unlike the while loop, which evaluates the condition before the loop body is executed, the do-while loop evaluates the condition after the loop body is executed. This guarantees that the loop body is executed at least once, regardless of the condition.

Syntax:

do {
// Block of code to be executed
} while (condition);

Example:
Let’s consider an example where we use a do-while loop to print numbers from 1 to 5:

public class DoWhileLoopExample {
public static void main(String[] args) {
// Initialize the counter
int i = 1;

// Execute the loop body at least once and then check the condition
do {
System.out.println("Value of i: " + i);

// Increment the counter
i++;
} while (i <= 5);
}
}