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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Overriding equals() method in Java

Short question: Why does Java allow overriding equals(), why is it not final? I am reading Effective Java 2nd edition by Joshua Bloch. I am a bit baffled by the conclusion that There is no way to ...
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49 views

Multiple 1024x1024 texture pages or one 2048x2048 texture page?

I have a lot of textures around the size of 512x512, and the LibGDX texture packer can't find a way to put more than one of those on one page for some reason. So, I end up with fifteen or sixteen ...
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2answers
163 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 ...
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3answers
114 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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4answers
240 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 ...
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0answers
126 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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4answers
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
456 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? ...
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2answers
272 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 ...
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5answers
237 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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1answer
98 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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3answers
207 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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2answers
342 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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0answers
85 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 ...
2
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5answers
758 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 ...
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0answers
57 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)? ...
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1answer
47 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 ...
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1answer
51 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 ...
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1answer
61 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 { ...
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2answers
133 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) { ...
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1answer
111 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 ...
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1answer
118 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 ...
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0answers
37 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 ...
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1answer
141 views

it is possible to implement keyloggers in java [closed]

I am researching on keyloggers and as a part of my research I would like to know if its possible to implement keyloggers in java edit * How can i create a keylogger in java or to be precise what ...
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2answers
202 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, ...
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2answers
114 views

Printing to out vs Logging, given the nature of this app?

I'm writing a command line application in Java. That app will scan a list of remote resources, do several attempts to access those resources, report failed attempts, and if succesfully accesed, ...
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1answer
132 views

Implementing a NoSQL and RDBMS compatible DAO

What would be the correct way to design a DAO which implementation is first going to be targeting a MS SQL database with a STAR model, but yet, business requirements specify the application must be ...
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2answers
96 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 ...
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2answers
193 views

Saving to file before storing into a database in a REST service

A mobile back-end I am building should receive a larger amount of data (some sensor recordings) from an Android phone. The phone does not have much use of it so it was most efficient to store the data ...
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1answer
113 views

Automatic Type Promotion in JAVA

I have started studying JAVA . In there, byte ch=50; ch*=2; works fine. But byte ch=50; ch=ch*2; does not. error:possible loss of precision required:byte found:int Why this do not happen ...
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7answers
2k views

Is there a pattern for a more “natural” way of adding items to collections? [closed]

I think the most common way of adding something to a collection is to use some kind of Add method that a collection provides: class Item {} var items = new List<Item>(); items.Add(new ...
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4answers
172 views

Options for constructing an object that is not logically initialized until all fields are set

I am working on a Pokemon game at the moment, and am running into some design concerns. The easiest example is as follows: Each Species of Pokemon has several traits that are required before it is ...
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3answers
483 views

Should I try it straight or should I first check if it can be done?

I have a set of items, and each item in the set must be unique. Item are composed from multiple properties and each property of each item can be changed. But after each change every item in the set ...
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2answers
93 views

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

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 ...
3
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4answers
416 views

Are `switch` statements generally used wrong? [closed]

I see most developers using switch statements with breaks in each and every case. Is this usage of switch statements inappropriate since a simple set of if-else statements would suffice? Is it OK for ...
0
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1answer
106 views

How to make my program do something when an errors pops up instead of crashing?

Basically i'm writing a game in Java where i want the program to tell the user that he can't move right or left if that move will cause the player to move out of the array, which means this: ...
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3answers
148 views

Should I be extracting strings from source in core java the way android does?

I just started doing android development stuff after getting pretty comfortable with Java. Android apps tend to do this weird thing where they have all strings for their program held in an XML file ...
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1answer
124 views

ActiveRecord equivalent in Java [closed]

My question is fairly simple.. What is the closest ORM to ActiveRecord that I'd be able to find for Java? In other words, in terms of thinking patterns and knowledge, with limted development time, ...
2
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3answers
160 views

Good or bad idea to create a “fromJSON” static factory constructor for an object that is often created by parsing a JSON coming from API?

I have a "Product" POJO class in my app. A Product object can either be created in-app by the user or by parsing a json that comes from the API. Product has 20+ fields, but Im using only 2 here for ...
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1answer
151 views

Adding a graphical view to a system

I currently have an program in Java that simulates railway movements. Essentially, trains arrive on platforms, pick up and drop off passengers, and then proceed, respecting signalling where possible. ...
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5answers
498 views

Should I create a single object for a common method call or use a throw away approach?

I'm creating a little rpg fight program just for fun and to practice my java (I'm pretty new hehe). I have a class called Dice with a method called d20 that rolls a random number between 1 and 20. ...
1
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0answers
141 views

How to separate out below tightly coupled classes

I have two classes which are somewhat tightly coupled to one another. Lets call them A and B. A derives from C and B derives from D. B is the class whose instance is created by the system and then B ...
0
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4answers
247 views

Identifying user of a webapp

For a small webapp I want to be able to identify a user. The issue is, if the user cheats in some manner, I want to be able to forbid him the usage of my application. I already have done extensive ...
1
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3answers
151 views

Limiting complexity in JPA programs Java/Hibernate

I've been working on a new application for some months now. It's my first big JPA program, and is still in the early stages. However, the complexity of my JPA object tree is becoming a growing ...
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2answers
107 views

How to randomly get or find a sub-tree (include root node) from a given tree that contains n leaf-nodes

I have a non-binary tree. I want to randomly find a "sub-trees" that are connected from root to leaf which must have at least n leaf-nodes (leaf-nodes of sub-tree must be leaf-nodes of given tree). ...
0
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1answer
105 views

Controlling concurrency by Thread Pool in scenario of CPU-intensive and I/O intensive requests?

My goal is to understand how to handle jobs coming from the client side at very high frequency each job is either CPU-intensive or I/O intensive, but both types of jobs are continuously arriving at my ...
3
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2answers
224 views

How should blank/empty value objects be instantiated/structured?

I was wondering... what is considered the best practice to instantiate blank value objects? (in Java) E.g. Assume we have some value object class Foo, that could be blank. Would creating methods ...
12
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2answers
555 views

Taming the 'utility functions' classes

In our Java codebase I keep seeing the following pattern: /** This is a stateless utility class that groups useful foo-related operations, often with side effects. */ public class FooUtil { ...
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1answer
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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 ...
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1answer
88 views

Bootstrap licence free template

I´m creating a new website. For that I´m using a free bootstrap template. On top of my index page I have: A Design by W3layouts Author: W3layout Author URL: http://w3layouts.com License: ...