Dylan Kwon

Thank you!

Hey everyone, I am have been prompted to download Oracle's "Lockdown Browser" to take the exam. Can this browser be used to take sensitive information from my computer? Can I easily delete it after my exam is finished?

Thank you, I understand fully now!

Mike Simmons wrote:Yes.

Thank you!

They have a set order and can be sorted, so they are sequential, and they have indices that allow you to access their elements in random order, so are they also indexed?

Piet Souris wrote:Say String s1 has length 5, and String s2 has length 10. In your first Comparator you return s2.length() - s1.length() = 5. Since that is positive, the first argument s1 is considered to be the bigger one and so will come after s2 in the sort. Your second Comparator does the reverse: since 5 - 10 is negative, s1 is considered to be smaller.

I see, thank you. What if s1 had length 10 and s2 had length 5? Or do we assume that s1 will always have a smaller length?

Thank you for clarifying!

For the Comparators, wouldn't both methods work for both scenarios? From my understanding, sort algorithms use compare methods to put values in order. Since both compare methods tell you if o1 is less than, equal to or greater than o2, why are they each used for 1 scenario?

1. Let's say I want a Comparator that sorts the longest strings first and there are no nulls values.

public int compare(String s1, String s2) { return s2.length() - s1.length(); }

I am told this is the correct method for doing so, but doesn't this method work as well?:

public int compare(String s1, String s2) { return s1.length() - s2.length(); }

Both methods return a number that signifies what string is greater, so isn't this enough information to sort?

2.
In a 2D array, letters does "letters[0]" refer to the 1st row?

Thank you for the clarifications! I have not studied Comparators well, so my questions are quite general.

This is the article I talked about: https://www.webucator.com/article/how-to-use-the-comparatorcomparing-method-in-java/

1: bigProject
|–source
||– Utils.java
|
|–classes

Is this the right way of reading this directory structure?
"|" means directory
"||" means a class within a directory.

So Utils.java is a class under the source directory, and classes is a separate directory.

2: If HashSets only have unique values, why did I have 2 values of 3 in the code below?

package TestPackage1; import java.util.*; import TestPackage2.SM; //import static TestPackage2.SM.*; public class Test1 {   public static void main(String[] args)   {      var nums = new HashSet();      nums.add((long)Math.min(5,3));      nums.add(3);      nums.add(16);      System.out.println(nums);   } }

Result: [16, 3, 3]

What is the following array declaration trying to accomplish? When I tried using a nested for loop to print its contents I got an infinite loop.

int[ ] nums[ ] = new int[ ][ ] { { 0, 0 } };

Result:
562433 0
1562434 0
1562435 0
1562436 0

and so on.

3
I have this block of code:
var list = Arrays.asList(“alpha“, “beta“, “gamma“); Collections.sort(list, _______________); System.out.println(list.get(0));

Either of the following expressions fill the blank so the code prints gamma:

(s, t) -> t.compareTo(s) Comparator.comparing((String s) -> s.charAt(0)).reversed()

How is the reversed method being applied to a character? Isn't this method used to reverse an entire array?
According to the article below, Comparator.comparing returns "a Comparator object that will use the specified field as the sort key."
What is the blank argument of the sort method supposed to be? And how do the methods above supply that argument?

Thank you for the help everyone! The bit about hexadecimal history was a pleasant surprise too.

To answer Liutaras' question, a = 3, and the result is 8. The complete code looks like this:

int a = 3; a = ++a + a++;

I'm guessing that when a variable is incremented, it doesn't completely change until after the operation. So right after "++a" we have 4 + 3. a becomes 7. Then after "a++" it becomes 8. So incrementing the a on the left side did not change the a on the right side.

Thank you so much, Paul this cleared up every question I had and more!

class X { static void m (StringBuilder sb1) { sb1.append(“er“); } public static void main(String[] args) { StringBuilder sb2 = new StringBuilder(“moth“); m(sb2); System.out.println(sb2); } }
Output: mother
For the above code, why does changing sb1, the parameter variable, change sb2?

public class Hemlock { static StringBuffer sb; StringBuffer sb2; public static void main(String[] args) { sb.append(new Hemlock().go(new StringBuffer(“hey“))); System.out.println(sb); } { sb2 = new StringBuffer(“hi “); } StringBuffer go(StringBuffer s) { System.out.print(s + “ oh “ + sb2); return new StringBuffer(“ey“); } static { sb = new StringBuffer(“yo “);} }

Output: hey oh hi yo ey
For the above code, why is "hey oh hi" appended before "yo?"

Hey everyone, I thought of these questions after taking practice tests.

What does 0xb mean?

As shown in the attached file, do user-created constructors automatically have the default constructor built into them?

What will variable a be after “a = ++a + a++;”? 8 or 9?