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.

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8
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8answers
1k views

What stops C from being compiled/interpreted/JIT'ed?

Java is often praised for its amazing portability, which I presume is because of the JVM. My question is what stops C from being being compiled/interpreted/JIT'ed.., if so, C can also be write once ...
1
vote
2answers
157 views

Is there a hashCode()-like method that can be used for state checking?

I thought up a simple and efficient way to combine states with events to make event handling more efficient. My idea of state checking involves State objects that hold reference to mutable variables ...
1
vote
2answers
102 views

distinguish requests from the same vehicle

I am implementing an small app to track buses based on Crowdsorcing. The riders send data long, lat, mac, route to the server as JSON string. In my database I have table bus to insert the transmitted ...
1
vote
1answer
73 views

Method documents differs between Java docs and Android docs

Some times I see problematic differences between Java doc and Android doc in about method documents.For example in about setReadable (boolean readable, boolean ownerOnly) method you can see java doc ...
2
votes
3answers
112 views

Database view performance - good practice?

Often times at work we opt to create views in the database to expose the data that we want to work with instead of building some monster query in our code. Being somewhat new to this field my ...
2
votes
2answers
80 views

Testing strategy for wrapper class

In my Android project I decided to create wrapper around SharedPreferences(which is basically key-value storage) with following interface interface Preferences{ public void saveInt(int value, ...
1
vote
2answers
380 views

Class becoming God Object what pattern to use

I am developing Android app and my MainActivity is becoming God Object. By the way native Activity class implementation is some sort of God Object already. The problem is that my activity class is ...
0
votes
2answers
117 views

The best shard key for user authentication

For access to my API user should send login and password and get generated token for access. Account login password Suppose the size of account's table is very large. So large - so needs ...
0
votes
2answers
166 views

Name of data structure that's tree-like with multiple root nodes

I'm attempting to implement a data structure, and using a more traditional tree data structure, but I'm not using the root node as it holds no real value in the context I'm using it in. Ideally, I ...
1
vote
2answers
127 views

What is the algorithmic time complexity of this program?

I wrote a simple program in java to create and maintain Dynamic Arrays: public class DynamicArrays { private Integer[] input = new Integer[1]; private Integer length = 0; private Integer ...
2
votes
2answers
149 views

Is it worth it to use a message-queue framework in this case?

We have these things called "executions" that are run at certain times. They have a delay property that basically says "execute me after delay microseconds`. Currently we are using Cassandra as a ...
0
votes
1answer
42 views

Java Action Listener

Actually, I've got a confusion in Java while implementing action listener event. I can add action listener event by implementing the class with ActionListener and by ...
7
votes
4answers
799 views

Is the use of one-letter variables encouraged? [closed]

Is the use of one-letter variables encouraged in Java? In code snippets or tutorials, you often see them. I cannot imagine using them is encouraged because it makes the code relatively harder to read ...
24
votes
10answers
4k views

What's the proper way to model this real-world activity that seems to need circular references in OOP?

I've been wrestling with a problem in a Java project about circular references. I'm trying to model a real-world situation in which it seems the objects in question are interdependent and need to ...
2
votes
3answers
151 views

How to use one web page to create and edit database entries

My team and I are developing a java web application which allows our admins to create and edit "methods" which can later be viewed by other users. We are currently discussing the best way to ...
0
votes
0answers
34 views

Design of a Smartcard listener [duplicate]

I have the task to write a listener which detects smartcards inserted into a terminal and notifies all registered classes. The listener needs to be accessible from different parts of a large ...
4
votes
3answers
440 views

When is an object of real world a (computational) object in OOP world?

In an OOP design phase strategy, Any physical/conceptual object of a system can be modeled(considered) as computational object in your OOP designed program based on below two conditions: First ...
0
votes
1answer
97 views

What are the time and space complexities of this recursive method that reverses a singly linked list?

What are the Time and Space complexities of this Java method that reverses a singly linked list (of length n)? I'm more interested in knowing the reasoning behind the space complexity. Let me know if ...
1
vote
1answer
179 views

What would be the best way to implement priority based programming without adding too much of if-else processing logic

We need to add priority based programming in our application using java programming language. For example, there are three priorities that a phone can have: A1, A2 and A3. Also there can be three ...
0
votes
1answer
114 views

Design: Bridge Game [duplicate]

I'm making revisions to a Console version of contract bridge I made in Java. The source can be found here: Bridge So most of the code is terrible and I've been trying make improvements wherever ...
1
vote
1answer
326 views

Avoiding lot of roles implementation in same object

Motivation Let a project where... ... exists a lot different behaviors. For each behavior, there is an interface which has its possible actions. One object could perform a lot different behaviors. ...
1
vote
2answers
140 views

Non-null alternative to Void (Java unit type)

I have a map-like type SmurfMap<K, V> which in certain contexts I use as a set-like SmurfMap<K, Void>. Implementation details forbid the values of the map from being null, so I cannot ...
1
vote
1answer
126 views

Design pattern for ensuring the “signature” of generic lists is equal

I have an interface, Attribute, that is going to be implemented in various ways, class AttributeA implements Attribute{\\..} class AttributeB implements Attribute{\\..} Then I'm planning to have ...
1
vote
1answer
138 views

Is a class representing a JSON response a DTO, a domain object, or something else?

Consider a restful service in Spring MVC. I am wondering how to package my response classes, i.e. how to name the containing package. First I thought of them as being domain objects. But they are ...
0
votes
1answer
119 views

Converting from List<Object> to Array with threads

I have a large (>500.000) list of Objects and I want to convert it a multidimensional array. Until now I am doing this using a for loop, but after some measurements I identified that this is a ...
1
vote
2answers
45 views

Expressing interface inheritance in natural language [duplicate]

In object-oriented programming, when you extend a class you establish an is-a relationship between a new subtype and its parent(s), i.e. B is an A (aka code inheritance). When you compose a class with ...
1
vote
2answers
144 views

Designing Message class in Java

I'm writing a class for Message. Message comes with Header and Payload. Header has following fields: Version Type For Type "XYZ", the following Payloads are allowed. Configuration Metafile ...
5
votes
2answers
168 views

How do I deal with the following technical issue? [closed]

I am a Java Programmer and I am relatively new to Java(1 Year). I am working for a small startup company. My problem is a bit strange and I am facing it a bit difficult to deal with and explain also. ...
3
votes
3answers
109 views

Would implementing a “Throwable Event System” be abusive?

I have been thinking for a couple years now about using Throwable events and implementing a sort of event system that uses throw to dispatch an event, or let a different method handle it with throws. ...
-2
votes
2answers
118 views

How would you structure your code for a Neural Network? [closed]

I understand how Artificial Neural Networks work. However, implementing one in code is quite another thing. How would you go about designing the classes and data structures? I found one great ...
0
votes
0answers
21 views

How to illustrate the difference between forward and backward compatibility [duplicate]

Please correct me if I'm wrong, but a new version that can run old code is backwards-compatible and an old version that can run new code is forward-compatible (like an old B/W television can receive a ...
0
votes
1answer
57 views

Getters with data conversion in Java VOs

I am working on a standard Spring application where DAO layer returns entities to service layer and service layer returns VOs to other services and controllers. In a certain scenario, we have a VO ...
3
votes
2answers
135 views

Domain object model: query by id vs object

Let assume I have two simple model classes: Product and Brand It is obvious I have a query method in Product class like this Product product = Product.findById(123); What if, I want to query ...
0
votes
0answers
35 views

Handling server failure using serialization

In my program, there is a central server, and I want to store its state. I'm using serialization for this, I am serializing the data after every 2,3 seconds. So that whenever server fails, it can come ...
1
vote
1answer
125 views

Differences in design/thought process for OO in Java and JavaScript [duplicate]

Despite sharing a similar name and syntax, Java and JavaScript are quite different. However, they both have Object Oriented features. As a JavaScript novice, the main differences that I can see ...
2
votes
3answers
146 views

How do I show 'creates' in a UML class diagram?

Let's say my code is going to look like this: public class MyController { private Foo foo; private FooGenerator fooGen; //setters public void work() { this.foo = ...
1
vote
3answers
184 views

Using prefix/postfix increment operator for simple incremental array access rather than actual index numbers

I cannot decide which method is better with consideration of both readability and fault-tolerance. Method #1: Object[] objects = getArrayOfKnownLength(); int i = -1; someMethod(objects[++i], ...
-2
votes
1answer
87 views

Java - Concept question: LinkedHashMaps vs POJOs?

EDIT: I'm just going to ask a single question instead of presenting a problem and asking for advice on a specific design decision in the solution. Given a batch of data from a database, collected ...
2
votes
2answers
182 views

return a object without returning the reference

i'm having some trouble with returning objects and lists of objects. To problem is I want to return a object in my example an developer but I don't want to give the reference. What's the best ...
1
vote
2answers
128 views

how can the presenter or view interact with the model in the MVP pattern?

I'm learning the MV* patterns. MVP in this case. I'm trying to refactor an old android application into the MVP pattern to make things less tightly coupled, but I'm struggling one one concept. I know ...
4
votes
5answers
475 views

Is it okay to go against all-caps naming for enums to make their String representation simpler?

Several times I've seen people use title-case or even all lower-case naming for enum constants, for example: enum Color { red, yellow, green; } This makes working with their string form ...
0
votes
1answer
77 views

Using Websocket for a multiple-page website

Is using Websocket (in particular, in a Java, SpringMVC webapp, with the Spring Websocket support libs, but the question probably applies to any language) for a multiple-page website a bad idea ? ...
5
votes
2answers
204 views

Does sun.misc.Unsafe give access to the system or just the JVM?

Please note: Although this question involves microcontrollers, it is at its core, a Java question, and so I believe it can be answered by any battle-weary Java guru. I stumbled accross this blog ...
1
vote
0answers
65 views

Will using a pure MQTT approach be the right decision?

I plan to provide additional functions for a closed-source 3rd party point of sales application. That application is used in restaurants, is run on Windows and uses dbase style databases. I know the ...
60
votes
9answers
10k views

How do you avoid getters and setters?

I'm having something of a hard time with designing classes in an oo way. I've read that objects expose their behavior, not their data; therefore, rather than using getter/setters to modify data, the ...
3
votes
3answers
165 views

Design suggestions for converters in Java

I'm trying a set of converters which will convert an object to some older form. And there are different objects which are converted. By older form I mean changing the values of some fields and in case ...
6
votes
3answers
244 views

Advantage/Disadvantage of having all variables declared in a JUnit Test

I've been writing some unit tests for some new code at work, and sent it off for a code review. One of my co-workers made a comment about why I was putting variables that are used in a number of those ...
15
votes
2answers
2k views

Declaring a class final? [duplicate]

I like my code to be written well; however, I have run into not really an problem, but more of a question about conventions. Say I have this class. public class Test { public void doStuff() { ...
0
votes
0answers
44 views

Run fat jar as a service on Amazon Linux EC2 instance using Ansible

I want to deploy a Ninja app to an EC2 Amazon Linux instance using Ansible. Being a Linux noob and completely new to Ansible, I wonder what the best way would be to start the app via Ansible as a ...
0
votes
1answer
43 views

Java: Weighted Selection help [closed]

I have this code that randomly selects a item from a enum. Each of the enum items have a integer weight to it. The higher that weight is, the higher chance that item has of being picked. Here's what ...