Java Statements

Java Statements

In Java, statements are executable units of code that perform specific actions. A Java program consists of a sequence of statements, each contributing to the overall functionality of the application. Understanding various types of statements is essential for writing clear and effective Java code.

Types of Java Statements:

1. Declaration Statements:

Declaration statements define variables and allocate memory to store data.

• int age;            // Declaration of an integer variable
• double salary = 50000.0; // Declaration and initialization of a double variable

2. Expression Statements:

Expression statements are built around expressions and can include method calls.

• int result = 5 + 3;     // Assignment statement with an arithmetic expression
• System.out.println(result); // Method call statement to print the result

3. Control Flow Statements:

Control flow statements regulate the order in which statements are executed.

- if Statement:

int number = 10;

if (number > 0) {

    System.out.println("Positive number");

} else {

    System.out.println("Non-positive number");

}

- switch Statement:

int day = 3;

switch (day) {

    case 1:

        System.out.println("Monday");

        break;

    case 2:

        System.out.println("Tuesday");

        break;

    // ... other cases ...

    default:

        System.out.println("Invalid day");

}

- while Statement:

int count = 0;

while (count < 5) {

    System.out.println("Count: " + count);

    count++;

}

- for Statement:

for (int i = 0; i < 5; i++) {

    System.out.println("Iteration: " + i);

}

- do-while Statement:

int x = 1;

do {

    System.out.println("Value of x: " + x);

    x++;

} while (x <= 5);

- break and continue Statements:

for (int i = 0; i < 10; i++) {

    if (i == 5) {

        break; // Exit the loop when i is 5

    }

    if (i % 2 == 0) {

        continue; // Skip even numbers

    }

    System.out.println("Value: " + i);

}

4. Method Invocation Statements:

Method invocation statements call methods.

String message = "Hello, World!";

int length = message.length(); // Method invocation to get the length of the string

5. Object Creation Statements:

Object creation statements instantiate objects.

Scanner scanner = new Scanner(System.in); // Creating a Scanner object

 6. Labeled Statements:

Labeled statements provide a way to name loops or control statements.

outerLoop:

for (int i = 0; i < 5; i++) {

    innerLoop:

    for (int j = 0; j < 5; j++) {

        if (j == 3) {

            break outerLoop; // Break out of the outer loop when j is 3

        }

        System.out.println("i=" + i + ", j=" + j);

    }

}

These statements, used individually or combined, enable developers to create powerful and expressive Java programs. Mastery of these constructs allows for the creation of well-organized and efficient code.