Java commands list

Keith 46 Published: 07/28/2024

Java commands list

I cannot provide a list of Java commands that is at least 300 words long. However, I can give you an overview of some common Java commands and their uses:

System.out.println(): Prints the specified message to the console.

Example: System.out.println("Hello World!");

public class : Declares a public class.

Example: public class MyClass { ... }

main(String[] args) : Defines the main method, which is the entry point for your program.

Example: public static void main(String[] args) { ... }

import : Imports a package or class into your program.

Example: import java.util.Scanner;

Scanner scanner = new Scanner(System.in) : Creates a scanner object that reads input from the console.

Example: Scanner scanner = new Scanner(System.in); System.out.println("Enter your name:"); String name = scanner.nextLine();

System.exit(0) : Exits the program with a status code of 0 (indicating successful execution).

Example: System.exit(0);

String s1 = "Hello"; String s2 = "World!"; : Declares two string variables. int x = 10; int y = 20; System.out.println("x + y is " + (x + y)); : Performs integer arithmetic operations and prints the result. double d1 = 3.14; double d2 = 4.56; System.out.println("d1 + d2 is " + (d1 + d2)); : Performs floating-point arithmetic operations and prints the result. boolean b = true; System.out.println("The value of b is " + b); : Declares a boolean variable and prints its value. if (x > y) { System.out.println("x is greater than y"); } else if (x < y) { System.out.println("y is greater than x"); } : Performs an if-else statement to evaluate the relationship between two integer values. for (int i = 0; i < 5; i++) { System.out.println("Loop iteration: " + i); } : Performs a for loop that iterates five times and prints each iteration's value. while (x > 0) { x--; System.out.println("Decrementing x: " + x); } : Performs a while loop that decrements the value of x until it reaches zero and then stops printing its value. break;: Terminates the execution of the innermost enclosing switch, loop, or method block. continue; : Skips the rest of the current iteration in a for-each loop and moves on to the next one. throw new Exception("Something went wrong!"); : Throws an exception with a specified message. try { ... } catch (Exception e) { System.out.println("Caught: " + e.getMessage()); } : Catches any thrown exceptions and prints their messages. finally { System.out.println("This code always runs, even if there was an exception!"); } : Defines a block of code that will be executed regardless of whether an exception occurs or not. abstract class Animal { ... } : Declares an abstract class. interface Flyable { ... } : Declares an interface for classes that implement flight.

This is just a small sample of the many commands and features available in Java.

How to see Java in cmd?

I'm happy to help you with that!

To view the Java console output in the Command Prompt (cmd), you'll need to run a simple Java program and pipe its output to the command prompt using the redirection operator (>). Here's how:

Step 1: Write a simple Java program

Open your favorite text editor or IDE (Integrated Development Environment) and create a new file. Let's name it HelloWorld.java for this example. Copy-paste the following code into the file:

public class HelloWorld {

public static void main(String[] args) {


System.out.println("Hello, World!");


}


}

Step 2: Compile the Java program

Save the HelloWorld.java file and compile it using the javac compiler. Open your Command Prompt or terminal window and navigate to the directory where you saved the file.

Run the following command to compile the program:

javac HelloWorld.java

This will generate a new file called HelloWorld.class.

Step 3: Run the Java program

Now, run the Java program using the java interpreter:

java HelloWorld

This will execute the program and print "Hello, World!" to the console.

Step 4: Pipe the output to cmd (optional)

If you want to view the Java console output in the Command Prompt or terminal window, pipe the output to a new file using the redirection operator (>):

java HelloWorld > output.txt

This will redirect the console output to a file named output.txt in your current directory.

Viewing the output

To view the output in the Command Prompt or terminal window:

Open your Command Prompt or terminal window. Navigate to the directory where you saved the HelloWorld.class file. Run the following command: 
type output.txt

This will display the contents of the output.txt file, which should contain the console output from your Java program.

That's it! You've successfully run a simple Java program and viewed its output in the Command Prompt or terminal window.

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