Java (not to be confused with JavaScript) is a class-based, object-oriented, strongly typed, reflective language and run-time environment (JRE). Java programs are compiled to bytecode and run in a virtual machine (JVM) enabling a "write once, run anywhere" (WORA) methodology.
2
votes
0answers
34 views
Travelling salesman implementation
I am working on an android application the travelling salesperson problem (a list of cities and the distances between each pair of cities, counting shortest possible route that visits each city ...
1
vote
1answer
31 views
Improvements for ugly reflection
I have a project that uses a library to save serialized objects in items and loads them again, when needed.
To do the de-/serialization, this library uses Gson.
Due to how Gson works and how the ...
3
votes
2answers
72 views
Foobar Fuel Injection Perfection efficiency
I was writing this code and was using the BigInteger class because it needs to work with numbers up to 309 digits long, however it takes too long to run with numbers that are too big. I was hoping to ...
4
votes
3answers
89 views
Calculation of the money to be paid back to the employer
I'm a beginner developer and I wrote a simple program. How could be the code improved to meet best practices of the development? I mean if the names of classes or variables are enough self-explaining ...
5
votes
0answers
29 views
Spring JWT authentication using cookies
I'm working on a experimental code which allows users to authorize using JWT's jjwt library.
Here's what I have done so far on authentication and authorization flow....
5
votes
2answers
484 views
Object oriented design for access control
Problem Statement:
Design an employee swap in swap out system. The system will have a machine which records the swap in and swap out. The user can also login in a portal where he can check his ...
1
vote
0answers
46 views
Generating all permutations of a given array
I have written this Java snippet to generate all permutations of a given Array of a HashMap. Can this be done in a better way? ...
-2
votes
0answers
17 views
fxml switch one window to another window [on hold]
from the image view button is there if button press should open new window and my code from controller is
This is code is from main controller to call other fxml/load fxml
private Button ...
3
votes
1answer
32 views
ServiceLocator for easy and central access to replaceable parts
For a bigger project of mine, I needed a simple and extensible solution for easy access to replaceable Parts.
This example will show the usage:
Define an Interface, describing the replaceable part ...
3
votes
1answer
48 views
Simple Java Swing calculator for addition and subtraction
I have built a simple calculator using Swing that can perform two operations, addition and subtraction. I would like to extend the operations and add more functionality, such as multiply, divide, ...
1
vote
0answers
44 views
Continue or Terminate after catching Interrupted Exception? [on hold]
I have a while ( true ) loop that should run for the duration of the program. If it is interrupted or terminates, the program should also terminate.
In that loop, I occasionally call Thread.sleep () ...
1
vote
0answers
42 views
check for null before or after casting
I have a list of BasicDBObject that I fetch from my database. This is basically a JSON document converted into a java Object.
Let's assume that we have a ...
2
votes
1answer
67 views
Simple calculator about keybinding
This is code for a simple calculator. Can someone review it, so I can know if there is something wrong? I also want to know if I can link a keybinding to a JButton so I don't have to write an ...
2
votes
1answer
41 views
Spring MVC verification email sending service
I have a @Service to send verification emails. Here is the code of the service:
...
-1
votes
0answers
26 views
Method that produces a staircase [on hold]
I was tasked with writing a method that would produce a staircase like so:
I managed to do this using a 2D array but was thinking of ways I could improve the runtime of my code and or other ...
2
votes
3answers
63 views
Method that compares the scores of two players
I tackled this problem today and was wondering how I could possibly improve this code.
The objective of the method is to return an array with the respective scores of each player. The method takes ...
5
votes
1answer
41 views
Swing “Number Guesser” program
I have made a UI that guesses the number that the user is thinking of(0 - 100), and I am wondering if it can be improved(I guess this is simple AI). I tried to shorten it as best I could, but it still ...
0
votes
0answers
14 views
Android Canvas - Draw a line graph with a gradient whose color depends on the y value
I'm looking mostly for feedback on a solution of mine. I want to create a pretty line graph where the color of the line is dependent on the Y value, and a change in color at ...
0
votes
1answer
25 views
CodeForces Freshman exercise
There are 60 submissions from me to the very first beginner-freshman exercise at codeforces.com. Problem: 100985A - MaratonIME helps Pablito
I don't pass the tests because of Time limit exceeded (tle)...
1
vote
0answers
17 views
Download the contents of an HttpURLConnection while generating metadata
Working on a web crawler (again), except now I've had a lot more time to hone my skills. The largest bottleneck in my program, as is to be expected, is the actual downloading of the data, so I'd love ...
2
votes
3answers
95 views
Number-guessing game in Java
I created a java number guessing game. I used some of the same code twice. I would like to know how to further simplify it if possible (I am a java beginner).
...
2
votes
0answers
25 views
RxJava2 custom Observable
I'm trying to understand how to bridge receiver-based events to the Reactive world. I asked a question on SO and was pointed to a different approach. The author of that answer (David Karnok) is ...
2
votes
2answers
97 views
Number of prime numbers in a given range
I've written a method that should return the numbers of prime numbers in a given range:
...
-2
votes
0answers
24 views
chess problem (check the check) [on hold]
I am trying to solve the problem from http://www.programming-challenges.com/pg.php?page=downloadproblem&probid=110107&format=html
But system shows me - wrong answer. I have checked a lot of ...
3
votes
0answers
25 views
oEmbed provider servlet to handle four media types
I would like to add oEmbed tags to my site (I'm the oEmbed api provider). My api should respond the results based on the file type.
oEmbed Types has
Photo
Video
Link
Rich
My response to photo ...
-2
votes
0answers
16 views
Error when inserting data into a database using Spring and Oracle [closed]
I am a coding newbie, I have been learning spring and I get this error every time. I have tried googling and checking Spring and Java forums, but, I have been unable to find a solution that fits. This ...
2
votes
1answer
36 views
Tic Tac Toe in Android
I made my first Tic Tac Toe game on Android and I'm looking for a way to simplify, make the code more flexible and remove the hardcoded code. I managed to do this game by looking at different ...
-1
votes
0answers
31 views
Program Architecture for a Music Player [closed]
I am refactoring the code for a music player I wrote in Java/JavaFX.
I have a few key objects which are accessed throughout the program by various other classes. I think there will be four or five ...
0
votes
1answer
30 views
Two approaches to count occurrences of one char in a String in Java
I have two approaches:
First Approach:
...
4
votes
1answer
100 views
Remove duplicate chars from String
I have retackled this problem using the help I received from here: Remove duplications from a Java String but this time using a LinkedHashSet since previosuly I was ...
-2
votes
0answers
24 views
Java Input form [closed]
I need help doing my assignment I was supposed to write a java program where a user inputs his name, age and gender.I tried this code but it did not output the way I wanted.
This is my code:
...
3
votes
1answer
75 views
I finally solved the Birthday Problem using Java
I like to put ideas and mathematics into code whenever I am interested in the subject. Ever since I was introduced to The Birthday Problem I wanted to throw it into a Java program.
I started writing ...
1
vote
1answer
24 views
Iterative quicksort in Java
I have this quicksort implementation that relies on heap memory instead of actual stack. It uses two integer stacks for keeping track what subranges are yet to be sorted. When a partition routine is ...
0
votes
0answers
11 views
Taking input from DB using isel function and assigning them to different var to use them but because there is a pattern so i think,It could be shorten
Here is my code, observe what I'm trying is, to shorten this code, but due to the slight difference in name of the variables, I'm stuck. Though the pattern is same. Please help me out.
...
3
votes
1answer
72 views
Reading values from a file and assigning to another class
I'm assigning values to an object by passing it to another class. Basically, I'm reading values from a file and assigning it by passing it to another class.
This is the POJO class for the details in ...
1
vote
1answer
47 views
Overriding equals and hashCode vs providing only Single Instance on immutable Objects
Let's say we have a class SomeInt which holds just one single final int value:
...
3
votes
5answers
128 views
Get the last two digits of a string
What would be the most performant way to get the last 2 digits of a string?
For example: getLastTwoDigits("a1b2cd3e4ghi5jk") must return ...
3
votes
0answers
41 views
Structure of a serial port reading program
I am writing a serial port communication app. And I thought I could get some feedback about the general structure of the program. If I am doing MVC correct, etc.
Since this is a "large" program I ...
4
votes
1answer
49 views
Bouncy castle 128bit AES/CBC/PKCS7 in java
I have been trying to do some encryption-decryption using bouncy castle and with the available docs and samples on the internet I have managed to prepare the below. Though this works without throwing ...
1
vote
1answer
19 views
is it good practice to use relative path in xpath more than once [closed]
I am using Selenium Webdriver-Java to automate a web application.
Suppose the html is somewhat like below:
...
0
votes
2answers
83 views
Remove duplications from a Java String
today I tackled this coding challenge: Remove duplications from string.
I was thinking of either using a Hashmap or a Set but realized that a set might have a longer run time since the way it ...
1
vote
1answer
43 views
Is it a valid use case of using java.util.MissingResourceException?
I have a factory method that returns an Object based on a argument passed to it :
...
-2
votes
0answers
46 views
Google Foobar Level 4 Running With Bunnies [closed]
This is the Problem i am having problem with. I have written the code for it. but it is arrayoutofbound exeception for some unknown input.
You and your rescued ...
-3
votes
0answers
22 views
Choose the right collection interface [closed]
In an institute following information is maintained about the students
Student Class
...
5
votes
1answer
66 views
Parse and format date
I have the following code for taking a date in the form of a string yyyy-MM-dd HH:mm:ss (UTC timezone) and turning it into ...
5
votes
1answer
80 views
Wrap string at certain delimiters
The method receives an unformatted string and it needs to put line breaks after ';' or before 'i)' and 'i.', where i - integer.
If received a string like '; 1)', then it should add only one line ...
-1
votes
0answers
24 views
Member variable in generic abstract base class? [closed]
I have a hierarchical data model and am trying to implement their CRUD operations in my Web Application.
Currently I have code inheritance for CRUD operations of my entities (resources) as follows:
...
-1
votes
0answers
18 views
Digital signing XML message using Java [closed]
We have an unsupported application at my place of work which digitally signs XML messages using a certificate from a keystore that we want to replace. Im attempting to write a replacement application ...
2
votes
2answers
50 views
TapeEquilibrium Java Implementation
A non-empty zero-indexed array A consisting of N integers is given.
Array A represents ...
-2
votes
2answers
84 views
