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General Tips and Best Practices

Corretto, Open JDK Java for AWS [edit]

Amazon Web Service (AWS) have their own flavor of Linux, and so they tend to offer variants of popular packages especially tuned for Amazon Linux, Linux 2, Linux 2023 (at least as of 2023).


Scanner, Keyboard Input Quirks

For programs that may prompt users multiple times for keyboard input, sometime it is unclear if the scanner buffer is rereading input already provided.  To avoid that, it may make sense to reset the scanner using new which will flush the buffer and make sure the next token is something new from the keyboard.

import java.util.Scanner;  //  console input needs this

public class ScannerTest {
  public static void main(String[] args) {

    //  Creates a Scanner object
    Scanner input = new Scanner(;
    String s1;
    System.out.print("Type the string 'test' [press return]: ");
    while(input.hasNext("test") == false) {
      System.out.print("try again [press return]: ");
      s1 = input.nextLine();      

    //  this CLEARS the keyboard queue, weird input triggers without this
    input = new Scanner(;  
    System.out.print("Type any string for a product name [press return]: ");
    s1 = input.nextLine();
    System.out.print("You typed: " + s1);



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