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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Return message to Android client from java Server via tcp sockets [migrated]

I am a beginner in Android with intermediate Java programming skills. I am also just learning socket communication. I am trying to make a very simple client/server connection. I have Android app as a ...
1
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3answers
33 views

Java logging dependency for a low-level library

I inherited a lower-level open source Java network library. The library is intended to be used by higher-level application protocol libraries which are in turn used by application code. My library, ...
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2answers
53 views

Why can we use the same name for local variable in different scopes?

I was wondering why is it possible that we can use the same name for local variable in different scopes? Like we can have two methods which both can have variable with the same name. What makes ...
-1
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0answers
59 views

How to identify http requests made from a closed-source java app?

I am an avid Go player and play on the Kiseido Go Server. I would like to write an open source client for this, but the KGS protocol is a well-kept secret. Is there any way to catch the http ...
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1answer
292 views

MVC: How to Implement Linked Views?

I'm developing a java application to visualize time series. I need (at least) three linked views, meaning that interaction with one of them updates the others. The views are: A list represents the ...
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1answer
38 views

Use JSON objects or POJOs in back end service?

I'm building a back end service for mobile clients. The requirement is that the mobile clients will pass me a token, I'll use that token to talk to other systems (behind the company firewall) in my ...
3
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1answer
217 views

Scheduling a few CPU-intensive tasks

I need to schedule a small number of CPU-intensive tasks to run every so often, reading from shared data and writing to dedicated buffers. I don't necessarily want to roll my own scheduling, but am ...
-4
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0answers
24 views

How can I use two or more threads using same run method work on different arrays? [on hold]

I am working on a game that requires the 2 players to control the movement with same run method using multithreading...now i can draw the two different object separately(not overlapping) but cannot ...
-4
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0answers
40 views

Why 1 bytes has 8 bits? [duplicate]

Past time Latin language was used in computer for giving command ,Latin language has 256 characters,for represent 256 word 8 bits was used . 2^8=256 8 bits are enough for representing 256 character . ...
12
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5answers
1k views

How does one keep argument counts low and still keep third party dependencies separate?

I use a third party library. They pass me a POJO that, for our intents and purposes, is probably implemented like this: public class OurData { private String foo; private String bar; private ...
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2answers
182 views

A 'task' system which has an ending, to get ready for next task

I want to make a system, so that there are certain tasks. For example, let's talk about a game. I want to make it so there are 100+ tasks doing different things, but when the player's magic level is ...
0
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0answers
47 views

Java - Get Interface Generic Type

I'm trying to create an Interface with Generics which allows me to get the type of object in the generics but no matter what I try there's a syntax error. I've tried the following 3 methods. All of ...
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2answers
185 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 ...
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0answers
24 views

Compare Values from two spinner and display the result accordingly in android studio [on hold]

I am developing an android app for bus routes in android studio. both spinner holds the cities names. I want to compare the values of both spinner(dropdown) and display the result i-e bus number for ...
-1
votes
0answers
21 views

Best way to get data from database inside Thread Class in Spring [migrated]

Currently i am troubling that how to get data from database inside my thread class. I can't make bean of my thread class because new instance is created of thread on every request. MyThread.class ...
5
votes
2answers
407 views

When to fix something that is “wrong” but works fine

Short version: I wrote some code that is not done "the right way" because, when I wrote it, I didn't know how to do it. Now that I know how to do it "the right way", how do I decide how to fix it? ...
2
votes
1answer
215 views

DataMapper for a MMO game plugin to send packets

I am working on an plugin for some game-server. The information about the plugin is not really necessary. Few points you might find helpful to answer to this question: The server The server is ...
4
votes
2answers
216 views

Is it a good practice to burn business logic into Enums?

Let's have a simplified business logic like this: public enum BusinessLogic { STAGE_ONE(true, false, false), STAGE_TWO(true, true, false), STAGE_THREE(false, false, true); private final ...
4
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1answer
257 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 ...
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3answers
105 views

Should abstract classes be used to prevent instantiation

Is preventing the instantiation of a class a valid reason to make it abstract? For example, if I have a class called Gauge which has subclasses HeadingIndicator and AirSpeedIndicator, is it a good ...
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0answers
49 views

How to compute days between two date choosers [on hold]

How to compute days between two date choosers and show it inside the textfield; is this correct and what is the code should i input inside the settext Date date1 = this.dcStart.getDate(); Date date2 ...
0
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0answers
154 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 ...
0
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3answers
169 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 ...
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votes
1answer
74 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
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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
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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, ...
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0answers
65 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 ...
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2answers
300 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
votes
0answers
24 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
694 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
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1answer
118 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
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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
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0answers
40 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
696 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
43 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
143 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
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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
votes
0answers
25 views

Cross platform application framework [closed]

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
votes
0answers
38 views

I want to switch my programming platform [closed]

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
41 views

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

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
73 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
120 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
98 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 ...