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.

learn more… | top users | synonyms

4
votes
2answers
412 views

Why prefer non-static inner classes over static ones?

This question is about whether to make an inner class in Java static or not. I searched around here and on StackOverflow, but couldn't really find any questions regarding the design implications of ...
0
votes
1answer
166 views

Why does storm not supply a mechanism for supplying topology necessary dependent jars other than the fat jar?

Following is a question that I had posted at the incubator-storm-user mailing list (verbatim). I had decided to open up the question here as well, because it also contains a conceptual side to it, ...
2
votes
1answer
93 views

What's the right OO way to create a counter/inventory class that works for both differentiated and undifferentiated countables?

You are writing a videogame about trading beans. Red beans, black beans, pinto beans, you name it. As everybody knows all beans are the same. You write the "Inventory" class for a trader in that ...
-2
votes
3answers
308 views

High Level design vs Low Level design? [closed]

Folks i am not sure what actually comes under HLD and what under LLD? . I did google but most of the answers are contradictory and theoritical. Say i need to design the login process in web ...
1
vote
1answer
91 views

Accessing a remote server from desktop application

Web applications (.jsp / Java) have the advantage that they can be run from any client browser by putting a single URL into the address bar, and off you go. However, the average web application is ...
3
votes
4answers
218 views

Why is there no 'subclasses-only' access modifier in Java?

In Java, there are four available access modifiers for methods: public - any class can use this method. protected - classes in the same package and subclasses in any package can use this method. ...
0
votes
3answers
91 views

Wrapping a map with instance or static method

I have a java.util.Map<String, Object> object which different types of values in it. I don't want to cast whereever I do a get operation over this. To do this, I created different classes ...
-4
votes
1answer
61 views

How do we call database table entity in Java? [closed]

For each database table, I create an entity (object) which contains all columns of the database as Class fields. Now, how do we call these entities in Java? I could not find an official term so I ...
1
vote
1answer
97 views

Serpent Algorithm thats implement Cipher

How must i change the Standard Implemplementation of the Serpent Algorithm that i can use it with the javax.crypto.CipherInputStream or javax.crypto.CipherOutputStream? I must implement/extends the ...
0
votes
2answers
176 views

.properties files in regular src folder okay? [closed]

I work on a Java project with a suggested structure (separate src folders for java files and resource files). After moving the message / text related properties files to that folder, the externalize ...
1
vote
1answer
163 views

Where should I put bindings for dependency injection?

I'm new to dependency injection and though I've really liked it so far, I'm not sure where bindings should go. I'm using Guice in Java, so some of what I say might be specific to just Guice. As I see ...
7
votes
3answers
350 views

Object Identity and Mutability

I was reading a proposal for value types in Java, and I came across this sentence: "Object identity serves only to support mutability, where an object’s state can be mutated but remains the same ...
-4
votes
2answers
162 views

Java FOR loop - don't understand this example [closed]

I am currently teaching myself Java. I have working through a book but there is this example below which I am not sure what is happening... class Elements { public static void main (String[] args) { ...
0
votes
2answers
272 views

How to enforce good coding style in team? [duplicate]

Even if I don't like enforcing people to do things (and I believe that it may decline the productivity and cause anger), I really want to enforce good coding style. Is there a way to set up ...
0
votes
1answer
75 views

Making the server request with high priority

I need to connect to a server and do manipulation with respect to HTTP GET and POST for my application and the server is generally used to handle multiple users with heavy load and many users might be ...
1
vote
4answers
238 views

Alternatives to null values and option-like types

Related to this question i want to know if there is a concise way to eleminate null values out of code in general or if there is not. E.g. imagine a class that represents a user with birthday as ...
-10
votes
1answer
128 views

Unable to write the content to a file in Java [closed]

I am unable to write the contents to the file in Java. The program compiles and executes well, file gets created but content is not written. Here is my code: import java.io.*; import java.util.*; ...
2
votes
1answer
137 views

Naming test methods in Java [closed]

Over at codereview a comment hinted that using snake_case to name test methods is a good idea. This contradicted my views and I did some research and there seem to be a lot of examples that actually ...
1
vote
0answers
121 views

Should we encapsulate everything in a try{} block in a Try object?

Why can't I make a class for a Try including what I try and then run that in the try {} block? Why is it impractical? class DBConnectTry extends Try { TryResponse response[] attempt(TryObject ...
11
votes
6answers
589 views

alternatives to nested try-catches for fallbacks

I have a situation where I am trying to retrieve an object. If the lookup fails I have several fallbacks in place, each of which may fail. So the code looks like: try { return ...
3
votes
5answers
606 views

How should I handle exception that *should* never be thrown? [duplicate]

What is the best way to handle errors that shouldn't ever happen? My current way to do this is to throw an exception if the 'thing that shouldn't happen' does happen, like so: /* * Restoring from a ...
1
vote
2answers
94 views

Design for reusable java module which uses DB connections

I'm tasked with changing some procedural Java code into Object Oriented re-usable module. It's an XML generator utility which uses velocity for XML generation. There are also business rule ...
0
votes
1answer
143 views

Using JDBC to asynchronously read large Oracle table

What strategies can be used to read every row in a large Oracle table, only once, but as fast as possible with JDBC & Java ? Consider that each row has non-trivial amounts of data (30 columns, ...
2
votes
2answers
95 views

Is retaining intermediate objects as member fields a good idea in this case?

I'm currently writing a series of classes in java that are meant to translate a regular expression (written with the formal definition, not language-specific shortcuts) into a deterministic finite ...
1
vote
4answers
725 views

Why do C# developers newline opening brackets? [closed]

I've spent most of the last several years working mainly with C# and SQL. Every programmer I've worked with over that time was in the habit of placing the opening brace of a function or control flow ...
2
votes
3answers
135 views

How to test state of the object

I have a class DataImport with only two public methods public void fromStream(InputStream inputStream); public ImportCommand getImportCommand(); When I test it I send some test data to fromStream ...
2
votes
2answers
249 views

Dalvik + Java licensing question

This is a licensing question about the Dalvik and J2SE core libraries. In particular the license governing java.util.concurrent.SynchronousQueue. The license header of the class in the JDK source ...
0
votes
3answers
85 views

Checking for the presence of optional properties of an object

I'm designing a class that holds several types of data. Some of the properties are optional. For example, let's say I have a class that represents a person, and one of the properties is occupation. ...
6
votes
2answers
723 views

A new i/o library: a good idea or a really bad one?

For a long time I worked almost exclusively with input/output streams in java. However a few years ago I started exploring async I/O as well (e.g. running on jboss netty). However when working in the ...
-1
votes
1answer
191 views

Why is it considered a bad idea to compile a Java app natively? [duplicate]

There are native Java compilers in existence. They compile Java source code to native binary. However, they are rarely used and it is generally considered a bad idea to use one. Why so? The only ...
-1
votes
2answers
146 views

Is it possible to implement a native compiler for a 'managed language' such as Java?

In most cases, it is possible to create both a native compiler and an interpreter for a programming language. The compiler would simply convert the source code to machine code, and the interpreter ...
0
votes
0answers
42 views

URL and Controller structure for parent-child-relationship

I use an MVC web framework to create an application which contains a hierarchy: Location <1-N> Devices <N-M> Services I have a number of Locations. Each Locations can have several ...
2
votes
1answer
134 views

Java Communcation API not available for Windows [closed]

I want to write a program in Java using RS-232. But I am unable to find the java.comm Package for the windows. Which library should I use for this purpose? ...
0
votes
3answers
290 views

Understanding object-oriented programming: why is it important? [duplicate]

Just started learning about classes in C++ and I'm have trouble understanding why object orientated programming (OOP) is useful. I understand the syntax, how to use them etc. But I'm still confused ...
0
votes
0answers
185 views

Spring bean injection into a hibernate validator constraint

I have a controller method like listed below whose argument is annotated with @Valid to validate PasswordChange object using a Hibernate validator @Constraint. Both PasswordChange and a sample ...
0
votes
0answers
39 views

Specific class to pass a bundle of data from my Model to Controller or a simple Collection?

I am doing an Invoice application implementing MVC pattern design in Java. One of the features my application has to have is showing all info about a Customer: Personal data, Calls, Invoices, ...
0
votes
2answers
231 views

Java Singleton fields implementation

I have singleton in Java and I have realized, that I could make its fields static and it would work same way as regular instance fields. Would there be a performance / optimization difference? If ...
0
votes
2answers
51 views

Can I use a package visible constructor for creation?

I need a class where this can be done: // user program elder_tales.Player p = elder_tales.generate_player(); elder_tales.level_up_player( p ); but not: // user program elder_tales.Player p = new ...
1
vote
2answers
292 views

Just one class - Java

I've written a program in Java, it's only fairly small and I started programming and ended up just building one big class with everything inside it. The program works fine and exactly how I wanted it ...
18
votes
5answers
3k views

How would another popular language avoid having to use the factory pattern while managing similar complexity as in Java/Java EE?

Factory pattern (or at least the use of FactoryFactory..) is the butt of many jokes, like here. Apart from having verbose and "creative" names like ...
0
votes
2answers
267 views

How can I re-use object from another project?

I have a first project has a feature to viewing, inserting and updating an employee record, with this possibly I will create a java class for the UI and another for the database connection with ...
2
votes
3answers
275 views

Inheritance: Is code from superclass virtually *copied* to subclass, or is it *referred-to by subclass*?

Class Sub is a subclass of class Sup. What does that mean practically? Or in other words, what is the practical meaning of "inheritance"? Option 1: The code from Sup is virtually copied to Sub. (as ...
-1
votes
3answers
199 views

Finding the name of a video game with a picture of its cover (Python/Java) [closed]

For the past few days, I've been trying to figure out how to take an image of a video game cover (like this one) and get the name of the game from it. Initially I attempted to use Google's Search by ...
2
votes
2answers
290 views

Design Hash table with simple hash function

I want to learn to Design Hash table with simple hash function for better understanding. I understand that the hash table will work as long as the hash function maps each key to a non-negative integer ...
0
votes
0answers
86 views

2D Game Data Structure in OpenGL ES 2.0

I'm trying to come up with some data structures for rendering my map on OpenGL. It is going to be ~ 100x100 blocks(squares) total, with each block being around 100 pixels. However, the screen will ...
4
votes
3answers
622 views

What is the process of determining which method in a class hierarchy should execute known as?

I thought I understood inheritance and polymorphism, but I was given this question, and I can't, for the life of me, figure out what the proper answer is or what they're trying to get at: The ...
0
votes
0answers
54 views

Suggestion to Design API Centric Application using Appengine

I have been planning to create an new application. So I was designing the application structure.i know this application will be accessed form multiple devices and the app feature will be increased. ...
0
votes
0answers
51 views

how to separate the logic of different views when using android viewFlipper?

I use a ViewFlipper in a dialog. I want to fetch the data from the EditText in both of them and also add click listeners to both of them. I can write the whole code in one big file, but i want to ...
3
votes
1answer
157 views

Should I assert in packages? [duplicate]

I have read a few asserts vs exception questions already; I ask specifically about package visible classes though. When you write a package, the classes marked with "public" are exposed to the ...
1
vote
3answers
133 views

Simple Design for Singleton function in java for Kernel [closed]

I understand that Singelton helps to instantiate only one class AT A TIME. I try to learn how to Design for Singleton function in java. I want to know it better to understand Kernel. So I try to do ...