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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3answers
428 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 ...
1
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1answer
529 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 ...
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2answers
1k 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 ...
2
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3answers
628 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 ...
8
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3answers
510 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 ...
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2answers
473 views

How to set up something like an integration server that measures the quality of code and reject the code if the score is below a certain number?

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
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1answer
426 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
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4answers
714 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 ...
4
votes
1answer
783 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 ...
2
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1answer
336 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 ...
12
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6answers
2k 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 ...
5
votes
5answers
2k 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
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2answers
404 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 ...
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1answer
600 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
172 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 ...
7
votes
4answers
11k 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
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3answers
303 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 ...
3
votes
2answers
418 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
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3answers
562 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
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2answers
977 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 ...
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2answers
381 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
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0answers
122 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
693 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
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3answers
571 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 ...
1
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0answers
1k 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
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2answers
433 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 ...
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2answers
217 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
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2answers
322 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 ...
19
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5answers
4k 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
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2answers
872 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 ...
6
votes
3answers
722 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 ...
2
votes
2answers
3k 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
1answer
349 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 ...
5
votes
2answers
2k 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 ...
3
votes
1answer
187 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
161 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 ...
1
vote
3answers
537 views

Empty superclass for Collection of derived classes

Basically, what I would like to obtain is a way to iterate through ONE list, and call methods specific to the interface the objects in the collection implement. In my Java project, it would result in ...
2
votes
5answers
1k views

how to design a stack without using java library or using list [closed]

I have a question how to design a stack without using list or array? This is one question that I want to think about as I want to better understand stack.
-1
votes
1answer
396 views

Should I label class diagram variables as private or public?

In my program, I have several class variables whose access specifier is known as private package. The default accessor specifier in Java is known as private package where it is accessible within the ...
0
votes
1answer
516 views

My UML class diagram is too complicated, what should I do?

Classes have 10-20 links with one another and you can't see anything in that mess of a diagram Unfortunately we finished coding already and if we change the class diagram we have to redo the whole ...
0
votes
1answer
183 views

Generics list without generics

I am using a very primitive Java that doesn't have Generics, and also I can't use reflection. I want to create a generic list so it would be typed safe (i.e. I only have a list that contains Objects ...
1
vote
2answers
314 views

What's the difference of an object being final and an object being immutable in java?

final String str = "do not change me"; str = "why not?"; //it will result in compile time error saying that final fields can not be re-assigned once created i.e. the reference cannot be changed ...
0
votes
0answers
359 views

Rich console UI

There are bunch of console programs and especially games using full redraw (not sure ho this correctly named) of console window. For example, look at output of linux top program -> ...
0
votes
4answers
292 views

Can a Java interface declaration enforce parameter properties?

As far as I know, declaring an interface is like so: public interface Roots_Squares { public double square_root( double value ); } Now... how do you enforce value to have non-negative values? ...
0
votes
1answer
172 views

Java code quality in methods calling methods

I am currently working with an "interesting" code-base and see the following type of thing alot in the code. public Object doSomething() { Object obj = new Object(); // Do some stuff to the ...
1
vote
2answers
467 views

How to manage data flow between UI components?

I have been trying to use classes that implement ActionListener to respond to user input. I'm consistently noticing that for an action listener to communicate the event to other objects, it has to ...
3
votes
3answers
298 views

how and should I 'unit test' an entire package?

I'm still learning to be good about doing unit level testing, as I've always been a little sloppy about only doing functional testing in the past, so I want to double check I'm doing this 'right'. I ...
2
votes
1answer
1k views

MVC design, singleton in model with initialization

I've recently learned of MVC (model view controller) and am trying to refactor an existing program. I am in a situation where I'd like to have exactly one object of a particular class so it seemed ...
0
votes
0answers
130 views

Algorithm / working approach to get a random list of data

I am working on a android schedule app but that isn't matter , the problem is a algorithm / methodology so you are welcome to just write the pusedo code to answer. The data is like this Place ...
0
votes
1answer
207 views

Familiarize with unknown source code [duplicate]

I have to continue feature development, issue fixing of a halfway completed code base. There is a no documentation, all developers had left the company. The technology stack is somewhat familiar to ...