Java is a high-level, platform-independent, object-oriented programming language originally developed by Sun Microsystems. Java is currently owned by Oracle, which purchased Sun in 2010.
-1
votes
0answers
13 views
Pointers to use org.xml.sax.EntityResolver.class [on hold]
I have a small situation while implementing the org.xml.sax.EntityResolver.class.
The sample XML file that's used to reproduce XXE attacks is provided below.
<?xml version='1.0' encoding='UTF-8'?&...
19
votes
5answers
2k views
Should non-trivial conditional statements be moved to the initialization section of loops?
I got this idea from this question on stackoverflow.com
The following pattern is common:
final x = 10;//whatever constant value
for(int i = 0; i < Math.floor(Math.sqrt(x)) + 1; i++) {
//...do ...
3
votes
2answers
59 views
Pattern for a method call outcome
Most often I need to call a service method from a controller, and based on the outcome, if there's an error show an appropriate error message depending on the error (or some other action, showing ...
0
votes
0answers
17 views
Implementing Data Type Independent User Set Values
I'm trying to set up a very simple user defined variables that can be set in an administration panel and used in the system. Our application is going in the direction of configuration over custom ...
-4
votes
0answers
29 views
How to overcome the timeout issue during an ElasticSearch call from Spring Microservice?
We are using Spring Microservice. We need to implement a Java library that makes ElasticSerach calls using Jest as our ELK Client API. The exposed interface of this library would then be used by the ...
7
votes
4answers
269 views
Subtyping without adding state or behavior - Bad Practice?
Observation
There are many Exception subtypes that don't have any added state or behavior. For example, ClosedByInterruptException code.
Question
Why is subtyping without adding state or behavior "...
-2
votes
0answers
44 views
Easiest way to develop a web app in Java [closed]
It seems like developing a Web App in Java is simply not a straight forward process. From the hosting to selecting a framework and a dom to the template engines it seems like you have 100 different ...
1
vote
2answers
173 views
How come language designers don't upgrade their global functions?
For example, when working with arrays there are methods like indexOf() that works like this:
if (array.indexOf("something")!=-1) { // do something or nothing }
Why hasn't someone made a contains ...
1
vote
1answer
85 views
Is it a good programming practice to store java properties keys in ENUM for validation once application starts?
Sample Java properties file which is read by the properties class
appl.component1.property1=value1
appl.component1.property1=value2
Custom class which extends the java.util.Properties class adding ...
1
vote
0answers
73 views
Is Java for server runtimes like JBoss EAP / Wildfly still free to use? [closed]
With Oracle starting to collect license fees from different customers for using Java SE I've asked myself if the usage with a server runtime is still free. I'm no lawyer and all these licenses are ...
-2
votes
0answers
72 views
How to create an application to look up users from a database? [closed]
Following is a problem that I am trying to solve:
If I have a database of 2 million employee records each of which
includes a first name, last name, company id(unique for every
employee), and ...
-1
votes
1answer
25 views
method to check nested transaction
So I am writing a method to check and throw if a new transaction is being made in another transaction.
I first came up with straight forward checkNestedTransaction, but this seems vague since I cannot ...
1
vote
1answer
73 views
Generating a Beta Reduced Lambda Expression in Java
Good day, I'm a beginner in Java and I was wondering if, in Java, I'm able to do a beta reduction with a given lambda expression in Java. Basically lambda reduction is like this:
1.)
Expression : (...
8
votes
2answers
122 views
Is it ok to have dependencies inside a class that's meant to be exchangable?
Let's say I'm having a domain-model and I want to read and save it from any persistence layer - right now it might be a json file but in the future it could be xml or a database (which might also ...
3
votes
1answer
37 views
How would you create a custom CDI @ProcessScope?
I am coding a Java EE application that provides REST services via JAX-RS resource classes, the application makes extensive use of CDI.
My resource classes are @RequestScoped, the application returns ...
3
votes
1answer
71 views
Contract interface/class with inner classes/interfaces
Brief description of my project structure.
I have some base classes like BaseView, BasePresenter ... .
Also my project consists of modules, module represents one complete part of the application.
...
10
votes
5answers
881 views
Is “static interface” a good practice?
I've just recently noticed there is an option to have static methods in interfaces. Same as with static fields of interface, there is an interesting behavior: These are not inherited.
I'm unsure it's ...
-1
votes
1answer
70 views
Question about the Java objects' equals() method
I have a question about the object X.equals(Y).
I use Sonar and it says that I have to move the "" string literal on the left side of this string comparison: !date.equals("").
So I did that: !("")....
3
votes
2answers
65 views
Value object that depends on multiple aggregates' lifecycle in DDD
During prototyping a simple ddd application from public transit domain I've faced a problem with one value object - Transit Pass:
Each Customer can buy a transit Pass thatallows a passenger of the ...
4
votes
2answers
74 views
Java Properties Files for Both Operations and Developers
We have an enterprise application. Maven build, about 20 submodules with more submodules. We have a dedicated Ops (operations) which deploys our application to 10 clusters. Installations are running ...
3
votes
2answers
165 views
Is expecting the API user to implement an UnsupportedOperationException okay?
I'm writing a handler for download/import of data. After inserting data to the database, several import jobs can be called, but usually it is just one. So there are two methods to get the import job(s)...
1
vote
1answer
122 views
Number equality / abstraction from precision and representation
I try to have find solution to get away from these heavy problems of number comparisons in Java... at least for numbers in a certain range with a certain precision with certain representation error.
...
6
votes
2answers
298 views
Is it considered a bad practice to create the Object.equals() method for testing purposes only? [duplicate]
Like the title says, is it a bad practice to create/generate the Object.equals() method because I need it in my unit tests, but not in my regular code?
-2
votes
0answers
29 views
Scala returning object type in if/else statements [migrated]
currently i have an abstract class called example, three case classes extending abstract class, and a function with a return type of example. in the function, when a certain condition is met, it is ...
3
votes
1answer
93 views
What are common Java dependency management strategies?
I am currently preparing a presentation for my software engineering class, in which I want to present the idea of package dependency management in Java on the example of "radial encapsulation" (http://...
-1
votes
3answers
141 views
Anonymous class as singleton
While implementing one of my modules, I needed a singleton for one of my classes, say, ModuleManager. Instead of creating a class with singleton criteria, I created an interface ModuleManager to ...
9
votes
7answers
2k views
Why is cyclomatic complexity that important for a single method?
I am using SonarLint for Eclipse since recently, and it helped me a lot. However, it raised to me a question about cyclomatic complexity.
SonarLint considers as acceptable a C.C of 10, and there are ...
1
vote
1answer
103 views
Pass result in API Chaining
We have set(6-8) of API and it will be invoked in a sequence . there are cases, want to use output of first/second API in the third/fourth API .
We have request object which is passed as input to all ...
19
votes
1answer
367 views
Does it make sense to measure conditional coverage for Java 8 code?
I'm wondering whether measuring conditional code coverage by current tools for Java are not obsolete since Java 8 came up. With Java 8's Optional and Stream we can often avoid code branches/loops, ...
5
votes
2answers
139 views
How to encapsulate internal classes in an API written in Java?
We have to write a library. Naturally, it should only have a very small API (as broad as needed as small as possible). The internals of the library are somewhat complex. Therefore, they need ...
3
votes
1answer
75 views
Parsing Multiple Files and Their Contents in Java using Multithreading without ExecutorService
I'm learning concurrency in Java and went over the tutorials on oracle website. While I have understood some of it, a greater portion eludes me. I was thinking of a hypothetical problem (though it may ...
3
votes
2answers
100 views
Mechanical State Estimator design
I want to write a library for Mechanical State Estimation of a vehicle. This is, estimate variables as position, velocity an so on, using the information provided by different sensor measurements (GPS,...
7
votes
4answers
245 views
Composition of two classes with common inheritance root
Hope your day is going well.
I want to make the following composition of two objects with the same inheritance root:
There will be 3 basic operations on the Wallet class: add, getCards and ...
1
vote
0answers
32 views
Spring MVC - Handling validation errors using the jQuery Validation plugin
Using jQuery validation, I send an AJAX request which is handled by the controller. The controller does send a response, but jQuery fails to insert the respective error message into the DOM. Instead, ...
1
vote
2answers
221 views
Java - Processing a large file concurrently
So at a high level my use case is as follows -
I periodically (every 24 hours) get a very large file (size can vary
from MBs to 10s of GBs) which I need to process within 24 hours. The
...
8
votes
2answers
170 views
Sharing DTO objects between microservices
TL;DR - Is it ok to share a POJO library between services?
Generally we like to keep the sharing between services strictly limited to none if possible. There has been some debate whether or not the ...
1
vote
1answer
80 views
How to design the system which executes two process independently with different configuration?
I have two process ProcessA and ProcessB. I want to run these two process independent of each other. There is no relation between them at all.
Each process should have a different Properties object.
...
4
votes
2answers
52 views
Deleting a node and returning the deleted node's value in a Binary Search Tree?
Hi I have a programming project where I'm basically using a Binary Search Tree to implement a min/max priority queue. I'm having trouble with the popMin/popMax methods. I get how to get the minimum/...
3
votes
1answer
130 views
Algorithms comparison and complexity
I want to sole this problem:
Write a method to return all valid combinations of n-pairs of
parentheses.
The method should return an ArrayList of strings, in which each string
represents a ...
2
votes
3answers
419 views
Should only static functions print to screen?
My question is more about trying to figure out if my belief is correct or valid in that a static method should be the only one that prints to the screen (let's say in a terminal). I am using Java and ...
1
vote
1answer
106 views
Message driven architecture and horizontal scaling
During working on a pet project in microservice event driven architecture, I've faced a problem of delivering responses to a client.
Each microservice (API Gateway etc) has many replicas and has it's ...
2
votes
0answers
179 views
Design elevator system algorithm and classes? [closed]
Here are the main classes I can think off the top of my head. All business objects will follow the abstraction (implement interfaces). I have not mentioned interface names
to avoid verbosity. I have ...
4
votes
1answer
138 views
Are there only 2 places you can declare new generic type parameters in Java?
It's confusing because type declaration and usage both use the <T> syntax. I think there are only 2 places where you can declare new generic types in Java:
1. In the definition of a class or ...
1
vote
0answers
46 views
Reuse of java beans for REST acceptance tests
We have acceptance tests for our REST endpoints using rest-assured. The tests currently have they're own fluent JSON builders. They help us remove noice from our tests. For example.
.body(someUser()....
4
votes
4answers
165 views
Indicating the end of a stream when null is a valid return
I have two kinds of data streams that both implement the same interface:
public interface DataReceiver {
public Data getData();
}
public class DeviceDataReceiver implements DataReceiver {
// ...
8
votes
4answers
589 views
What are the responsibilties of the main in object oriented programming?
I'm new to object oriented programming and I don't understand what's the purpose of the main.
Yes, I read that it's the "entry point" of the program but what I don't understand is what should be in ...
2
votes
0answers
51 views
Pattern for retrieving batches of Objects?
This seems to be a recurring requirement for me, so I'd like to get some feedback on how to implement it and what sort of test code makes sense. I need to retrieve batches of data and stitch it ...
7
votes
0answers
102 views
I need to write my own version of a bounded queue [closed]
I need to write my own version of a bounded queue. It must be thread safe. The consumption of this queue is based on a priority system, where a consumer makes a request for an object in the queue.
...
3
votes
1answer
85 views
Is avoiding having the fields representing the same object in different communicating classes reasonable?
I'm developing a program which does communication to different types of devices (with respective protocols). It should concurrently acquire messages from devices and write them to a file with specific ...
-1
votes
1answer
113 views
MVC with several MVC-patterns and gameloop
I made a small program using several MVC-patterns. So far I havnt got to much stuff to put in the model so I havnt got any model yet.
My idea is to make one MVC pattern for each panel. And looping ...
