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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144 views

How far to go when future proofing fluent-method-chained-DSL test code?

Is it worth implementing interfaces, or using the getThis() trick, or even static factory methods to future proof against the need to extend this DSL? The current design is a pair of thin ...
-2
votes
0answers
13 views

how to identify http requests made with a java app

I am an avid Go player and play on the Kiseido Go Server. The only client I know is the one app CGoban which operates in desktop Java (https://www.gokgs.com/download.jsp), or if you wish as a Java ...
0
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3answers
138 views

Why Double.parseDouble(“ABC”) not returns Double.NaN?

This code: Double.parseDouble("ABC") throws a NumberFormatException. Why is it wrong to expect a Double.NaN (NaN is literally Not-A-Number). A working example is this: public static void ...
-6
votes
1answer
58 views

Im a noob in programing and i tryed to create something like a rpg game can you tell me what you think about it and tell me if i can change anything [on hold]

import java.util.Scanner; public class JAva1 { public static void main(String[] args) { Scanner input = new Scanner(System.in); float MAtP, MSpP, MCHit, MHP, MSpeed; ...
51
votes
7answers
33k views

Why use try … finally without a catch clause?

The classical way to program is with try ... catch. When is it appropriate to use try without catch? In Python the following appears legal and can make sense: try: #do work finally: #do ...
17
votes
7answers
2k views

What can one do to improve readability of math-oriented code in C#, Java, and similar? [closed]

As both a C programmer and a C# programmer, one of the things I don't like about C# is how verbose math functions are. Every time you would have to use a Sin, cosine, or power function for example, ...
4
votes
1answer
167 views

Small code, big test

I have this code in a controller of an MVC implementation: public void execute() { try { String path = userSelectsFile(); if ( path == null ) return; //Just returns ...
0
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0answers
54 views

Best practices for programmatic describing of behavior of complex input forms

We have a complex web form (we use GWT/GXT stack) with lots of input elements of different types (text fields, selects, checkboxes, buttons), and behavior of these elements depends on each other. Now ...
0
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2answers
296 views

Is factory pattern a right pattern for the situation described here?

Is factory pattern a right pattern when we want to consolidate the related objects? Problem - In the Set-top box, I have a user-io, basically the interface to control the settop box - The user-io can ...
5
votes
2answers
2k views

Visitor stability vs instanceof flexibility

I am working on a GUI application which generates a configuration file. I have a class hierarchy for the configuration model and I use an object tree of that hierarchy in several different contexts. ...
-2
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0answers
20 views

Good tutorial for Atmosphere? [on hold]

What is your favorite tutorial for Atmosphere framework (async-io.org)? It's not much fun (for me, at least) trying to glue together atmosphere-examples and bits of info scattered through atmosphere ...
2
votes
5answers
668 views

Is it possible to make some methods invisible/non-usable to some classes in Java?

I am developing an application in Java whereby I would like to pass an object as part of an interface into other methods of classes written by other developers in the team. The object I'm passing in ...
1
vote
1answer
116 views

Debugging xml and annotations

By now, most web containers have an annotation variant of their xml configurations for Java EE. I'm guessing this is because it's better to keep things in Java where they can be managed, coded with ...
0
votes
1answer
321 views

Dynamic query in Mysql

I'm doing a J2EE web application with Struts2, Mybatis and a MySQL database, so what I want to allow to the user is to be free to choose different parameters to perform a select to a table in the ...
1
vote
0answers
27 views

Java MVC: multiple use of the same event for different actions

I am working on a large Java project which employs the model-view-controller pattern. Should I use a different event for each action (to let the views communicate with their respective controllers)? ...
-1
votes
1answer
695 views

Java: How to manage UDP client-server state

I am trying to write a Java application that works similar to MapReduce. There is a server and several workers. Workers may come and go as they please and the membership to the group has a soft-state. ...
0
votes
1answer
42 views

Is there an established pattern for associating a database entry with a Java class that executes on that data?

I have a behavior tree with different leaf nodes that execute tasks. When building out the tree relationship in the database I need an association between the leaf node entry and the Java class that ...
1
vote
1answer
141 views

Is this database design good? What JPA Entities should I create for this design?

I am trying my hands on JPA. For this I am thinking of using the example of a student admission process as shown in the diagram below. Is this design good ? Any suggestions for improvement are ...
63
votes
3answers
24k views

Choosing between Single or multiple projects in a git repository?

In a git environment, where we have modularized most projects, we're facing the one project per repository or multiple projects per repository design issue. Let's consider a modularized project: ...
27
votes
2answers
1k views

How have Guava unit tests been generated automatically?

Guava has unit test cases automatically generated: Guava has staggering numbers of unit tests: as of July 2012, the guava-tests package includes over 286,000 individual test cases. Most of ...
118
votes
13answers
26k views

Should we avoid object creation in Java?

I was told by a colleague that in Java object creation is the most expensive operation you could perform. So I can only conclude to create as few objects as possible. This seems somewhat to defeat ...
0
votes
1answer
37 views

Architecture question about data migration

I'm facing a new enterprise project in Java about data migration. I did one of them in the past, now I want to do a better work and I think I need your considerations. So, let's me explain the ...
-4
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0answers
24 views

Cross platform application framework [on hold]

I am planning to develop a cross platform application that will run on all operating systems mainly windows desktop, Mac desktop, android and Apple mobile devices. What are the cross platform ...
-4
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0answers
36 views

I want to switch my programming platform [on hold]

I have worked as a ASP.NET developer(Web) for 4 years and I waked on Desktop applications as well(WPF). As everyone knows many things are taken care by .net framework and by Visual Studios, as days ...
-3
votes
1answer
39 views

How should I change in get method without calling getList() of Deque? [on hold]

import java.util.List; import java.util.ArrayList; public class Test { /** * @param args * @throws Exception */ public static void main(String[] args) throws Exception { ...
0
votes
2answers
72 views

Classic ASP to Java UI Conversion

My question is based on a business model of a financial services organization that currently is supporting applications that are a hybrid mix of Classic ASP and Java, with some JSP’s already in some ...
1
vote
2answers
114 views

Is it better to perform a calculation in the field's setter or have a different method?

I'm implementing a simple Quota object which determines a usage percentage based on the maximum and the used. private int maximum; private int used; public Quota(int used, int maximum) { ...
0
votes
1answer
94 views

Enum as singleton or fully functional class [duplicate]

Joshua Bloch claims that "a single-element enumeration type is the best way to implement a singleton" Why? I totally disagree with this statement because enumeration is data type with some ...
-2
votes
0answers
37 views

Design pattern for Login Online and offline [closed]

I am new to Software Design patterns, I am developing an application in which user may liggedin offline or online depending on internet connectivity... so which design pattern will be best solution ...
23
votes
8answers
10k views

Why was Scala not implemented with C or C++

Does anybody know why was Scala implemented in Java and .NET instead of C or C++? Most languages are implemented with Cor C++ [i.e Erlang, Python, PHP, Ruby, Perl]. What are the advantages for Scala ...
22
votes
6answers
23k views

Difference between a service class and a Helper class

I would like to know what differentiates a Service class from a utility class or a helper class? A class only with underlying methods calls the dao's is a service? Doesn't the usage of Helper ...
0
votes
0answers
64 views

Transaction Management in Hibernate with DAO Design Pattern

I have many Tables, For every Table,we have DAO Interface and DAOImplementation class. Example DAO Interface public interface CancelPolicyDAO { public CancelPolicy insertCancelPolicy(CancelPolicy ...
1
vote
1answer
258 views

From a DDD perspective is a report generating service a domain service or an infrastructure service?

Let assume we have the following service whose responsibility is to generate Excel reports: class ExcelReportService{ public String generateReport(String fileFormatFilePath, ResultSet data){ ...
-3
votes
0answers
27 views

Suggestions for Subscription-Based Software Product Licensing [closed]

Can anyone suggest some solutions or products for doing subscription-based software product licensing? We have used dongle-based solutions in the past but, with the proliferation of virtualization, ...
-1
votes
0answers
37 views

Advice needed on Selecting Server VS Cloud [closed]

I am having a big issue. Imagine that I am planning to launch a local social media site. You know what it is, multiple users, lot of data uploads (ie: photos, notes, etc). However I am having a hard ...
-1
votes
0answers
16 views

How BeanPropertyRowMapper works internally in spring?

I know that BeanPropertyRowmapper use setter method when I fire select query but is it uses getter method too or not ? I don't want to make my custom row mapper or hibernate or JPA. I have face below ...
52
votes
11answers
6k views

Did the developers of Java consciously abandon RAII?

As a long-time C# programmer, I have recently come to learn more about the advantages of Resource Acquisition Is Initialization (RAII). In particular, I have discovered that the C# idiom: using (var ...
10
votes
4answers
805 views

Good implementation strategies for encapsulating shared data in a software pipeline

I'm working on re-factoring certain aspects of an existing web service. The way the service APIs are implemented is by having a kind of "processing pipeline", where there are tasks that are performed ...
-4
votes
0answers
49 views

About primitive types in java [duplicate]

I see that Java has Boolean (class) vs boolean (primitive). Likewise, there's an Integer (class) vs int (primitive). What's the best practice on when to use the primitive version vs the class? Should ...
0
votes
1answer
109 views

Should I use one class that calls Several static methods or several classes each calling one static method

I need to use instances which represent mathematical functions along with their parameters end enable their evaluation. I can take 2 approaches: 1: have a single class representing all the math ...
1
vote
2answers
143 views

How to add rigor to my testing?

I work on a small/medium sized Java application. Over time, I've tried to ensure that the tests which I write are "good" tests, and that there's plenty of them. Hence I've been looking into various, ...
-2
votes
0answers
43 views

Java : Error: A JNI error has occurred, please check your installation and try again [closed]

I am trying to run a new application which requires Java (Kaazing) and keep getting this error on startup "Error: A JNI error has occurred, please check your installation and try again" I have ...
2
votes
7answers
14k views

Understanding the difference between mutable and immutable classes

I faced this question in one interview. I explained that String is immutable and StringBuffer is mutable class. I don't know very much about mutable and immutable and also don't know the exact answer. ...
26
votes
13answers
2k views

Does the use of debuggers have an effect on the efficiency of programmers? [duplicate]

Possible Duplicate: Are debugging skills important to become a good programmer? I'm a young Java developer and I make a systematic use of the Netbeans debugger. In fact, I often develop my ...
1
vote
0answers
91 views

Finding ArrayList elements in ArrayList [migrated]

I have two ArrayList userActions and actionsToCheck of type enum Action. I want to check if all the elements in actionsToCheck is present in userActions. Is the following good enough or is there a ...
1
vote
0answers
29 views

Individual methods or parameters for Google Analytics abstraction on Android

A coworker and I are having a discussion around the best way to build our abstraction on top of Google Analytics for an Android application. A couple of data points. We have auto-tracking enabled ...
0
votes
1answer
471 views

HTTP Session: A single object or multiple?

I tested two approaches to store session data: The classic: 1 key, 1 object (And every key as static final String in a class) "user" --> UserObject "preferences" --> List ... An ...
-4
votes
0answers
50 views

Sending binary data along with a REST API request [closed]

The problem is I need to send binary data (for example multiple images) and some metadata information together. I am using REST based web-service.
1
vote
2answers
87 views

Java applets with Safari on Windows as compared to Safari on OS X [on hold]

I have a developed an Applet which works fine on Chrome/IE/FF on Windows. I am not expecting any users for Safari on Windows but there might be the odd user who may be on a Mac. As of now, I don't ...
15
votes
8answers
36k views

Why does java.util.ArrayList allow to add null?

I wonder why java.util.ArrayList allows to add null. Is there any case where I would want to add null to an ArrayList? I am asking this question because in a project we had a bug where some code was ...