What is JShell in Java ? JShell commands

What is JSHELL?

• JSHELL is the command line tools for Read/Evaluate/Print/Loop (REPL) Java Statements
• It can be used for learning Java Concepts
• The Java Statements executed in JSHELL is called as Snippets
• To run, type jshell in Terminal/Command Window

Minimum Java Version?

• Minimum JDK9 version is required to use JSHELL

JSHELL Commands

• /help - Getting help
• /exit - Exit JSHELL
• /list - List ALL Snippets
• /edit - Edit Snippet in Editor
• /save - Save Snippets into File
• /vars - List variables
• /imports - List imported packages
• /reset - Reset the current session
• Ctrl+l - Clear the Screen
• Ctrl+C - To exit from the current snippet

Use as Calculator (Java Operators Demo)

  10 + 20
  100 * 3863

Create a String

  String str = "Hello";
  str.toUpperCase()
  str.length()

Create a List

• Creatigng a Simple List
• Getting Dynamic Help of a Method (Press Tab after typing Char(s))
• List.of() vs Arrays.asList()

  var myList = Arrays.asList(4,5,3,1,2);
  myList.sort(Comparator.naturalOrder())
  myList
  myList.sort(Comparator.reverseOrder())
  myList

Create a Greet Method

• Simple method

  String display(){
    return "Welcome to JSHELL";
  }
  display()
  

• Method with Parameter

  String greetUser(String name){
    return "Welcome " + name;
  }
  greetUser("J shell Clear Screen")
  

Create a Boolean Method

• If-Else Statement

  boolean isEven(int n){
    if (n % 2 == 0) {
       return true;
    }else{
       return false;
    }
  }
isEven(10)
isEven(9)

• Conditional Operator

  boolean isOdd(int n){ 
   return (n%2 !=0)? true:false; 
  }
  

Save the Snippets into File

/save C:\Users\Anmol\Documents\Snippet.java

Mastering JShell Clear Screen Command

When diving into Java development with JShell, organizing your workspace efficiently becomes paramount. One handy tool in your arsenal is the 'clear screen' command. Imagine it as a magic wand that tidies up your cluttered workspace, ensuring your code shines through without distractions.

Introduction to JShell

JShell, Java's Read-Eval-Print Loop (REPL) tool, offers a seamless playground for testing snippets of code. Its interactive nature allows swift experimentation, making it an invaluable asset for both beginners and seasoned developers.

Understanding the 'Clear Screen' Command

In the realm of JShell, the 'clear screen' command serves a pivotal role. It wipes the slate clean, erasing previously executed commands and outputs, presenting you with a pristine workspace.

How to Use 'Clear Screen' in JShell

Using 'clear screen' is a breeze. Simply type the command ' /clear ' and hit enter. Voila! Your screen transforms into an empty canvas, ready for your next coding masterpiece.

But wait, there's more!

/clear

Benefits of Using 'Clear Screen' in JShell

Why bother with a clean slate? Think of it as decluttering your desk before starting a new project. It eases readability, ensuring your focus remains on the current task rather than sifting through past lines of code.

Advanced Techniques with 'Clear Screen'

Did you know you can tailor the clear screen command to suit your needs? Adding parameters can tweak its behavior, enabling it to cater to specific requirements within your workflow.

Best Practices for Utilizing 'Clear Screen'

While 'clear screen' is a powerful tool, like any other, it's essential to wield it wisely. Avoid overusing it, as it might disrupt your workflow or lead to accidental code loss.

'Clear Screen' vs. Other JShell Commands

Comparing 'clear screen' with similar functionalities highlights its unique role in maintaining a clean workspace. Unlike other commands, its primary focus is solely on resetting the screen.

Common Mistakes and How to Avoid Them

Mistakes happen! From forgetting the command syntax to inadvertently clearing essential code, we've got you covered with troubleshooting tips and alternative approaches.

Practical Applications of 'Clear Screen'

Let's bring theory into practice! Explore how 'clear screen' fits into debugging, testing, or when collaborating on complex Java projects. Real-world applications showcase its significance.

Future Developments and Enhancements

What's on the horizon for 'clear screen'? While it's already a handy feature, there's always room for improvement. Community feedback might shape its evolution in upcoming JShell updates.

Conclusion

In the vibrant realm of JShell, the 'clear screen' command stands tall as a facilitator of clarity and efficiency. Mastering its usage empowers developers to navigate their coding journey with precision and ease.

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FAQs

1. Can 'clear screen' retrieve erased code in JShell?

No, the 'clear screen' command permanently erases previous commands and outputs.

2. Does 'clear screen' delete saved variables in JShell?

No, 'clear screen' only resets the display, leaving saved variables intact.

3. Can 'clear screen' undo accidental deletions in JShell?

Unfortunately, 'clear screen' doesn't have an undo function. It's crucial to double-check before executing the command.

4. Are there shortcuts for 'clear screen' in JShell?

Yes, '/cls' serves as a shortcut for the 'clear screen' command.

5. Can I customize the 'clear screen' command in JShell?

No, as of now, 'clear screen' doesn't have customizable features. It functions uniformly across JShell environments.