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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53 views

What are the Pros and Cons of recursion over loops? [duplicate]

What can be said for the benefits and negatives of recursive functions over using a loop? For example. Is it just a matter of writing less code? Surely recursion has the potential to StackOverflow ...
1
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2answers
119 views

Is it a good idea to require passwords in offline applications?

I am developing an application which can install extension modules (plugins, if you will) from APT-style repositories hosted elsewhere. The plugins need not be signed (although the downloads are ...
1
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2answers
129 views

Smells in exception handling: how to separate between public and internal exceptions?

During the development of a small web API, we decided to separate internal exceptions from public exceptions. Public exceptions are HTTP exceptions, that translate into HTTP responses with proper ...
0
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0answers
21 views

do my “dal” and “fileHandler” interfaces overlap?

I want my program to: 1) read some input lines from csv file 2) write the output lines to plain string file 3) read some input from the same file in (2) and compare it to some calculated data. I ...
1
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0answers
80 views

Optimal data structure for binary data/Java

I have several input formats mostly restricted to geotiff and some proprietary binary formats. I import them into my program and then need to export them into various other data formats (also binary) ...
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0answers
20 views

Data Type of file_get_contents of php in java [migrated]

I am trying to upload an image to the database with blob datatype. I use web-service method addProfilePic that store the blob data to the database with my Codeigniter project. I retrieve the image ...
0
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1answer
87 views

advantage of having multiple REST web services

I have a application designed using Spring REST service. the application has two REST projects: Web Core Web has html, JavaScript and Java classes (ajax calls this REST). These Java classes in ...
2
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2answers
115 views

Does anyone else feel like confused even after they're done studying programming tutorial? [closed]

I am learning core java and I was studying from java trails on oracle website. When I was done learning the Thread trail, still there was a sort of confusion and blurriness at the back of my head. I ...
0
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1answer
30 views

Handling DomainExceptions using REST endpoint

Suppose I'm doing some DDD. Now, I have a microservice reflecting a bounded context/a part of a bounded context. Now, suppose there is a REST endpoint: '/somedomainmodel/someaction' My API user is ...
0
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0answers
41 views

How and where to make global function file in jsp sevlet web application

I am making a website in Servlet&JSP. I am looking for good way to make a specific function file from where I can call and declare my common functions. If I made a java file function. Java, so is ...
4
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1answer
134 views

What are the reasons for sealing a .jar and how would I verify that?

I have created a sealed jar, but I don't see difference compared to using a non-sealed one. What tests I can perform to verify the jar is sealed? What reason we could have to prefer using a sealed ...
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0answers
23 views

Minecraft Server - Get list of online players (Java) [migrated]

My question is: How do I get a list of online players, not the count of the online players, in Java? //So I could call... String[] players = getPlayers("fnaf.hosthorde.net"); That is how I'd like ...
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0answers
45 views

Possible way to make java class builder more abstract by using interface required keys

I'm looking for a more abstract pattern for builders that handles required fields without the need of writing a validator that checks if all requried fields are set. I like this builder. But is ...
0
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1answer
82 views

Is set of libraries called API only if it talks to a system/server?

I have read few articles about API. Can't find the reference now. In some of them, they define API as set of tools, routines and protocols which are helping programmer to build a software with use of ...
0
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1answer
33 views

best way to export binary data with additional text attributes to a stream

I would like to create a command line API in a Java application to export a binary blob to stdout. I would additionally like to export certain attributes about the blob, ideally in a non-binary ...
28
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8answers
4k views

Is throwing an exception an anti-pattern here?

I just had a discussion over a design choice after a code review. I wonder what your opinions are. There's this Preferences class, which is a bucket for key-value pairs. Null values are legal ...
2
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3answers
150 views

What is the difference between a variable and a parameter? [closed]

Its a conceptual question. But I would like to use the right term at the right place. That is why I would like to read some other views on this.
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1answer
83 views

Why java has so many frameworks [closed]

why java has so many frameworks? why core java is not sufficient enough to solve the problem or develop anything? Even if core java is insufficient enough that we need frameworks,why there are ...
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1answer
57 views

Servlets and JSP begginer help [closed]

I Just finished learning java fundamentals.It took me three days just to configure Apache tomcat into eclipse.Though I am familiar with eclipse, the whole Apache tomcat Interface looks very Alien to ...
4
votes
1answer
101 views

How would I isolate changes to mutable state if I need to run two queries to get the final result?

I'm working on some code that takes search criteria from a Rest API and uses it to query a remote API to return results. As an exercise, I wanted to try to separate all state changes to one place, as ...
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5answers
1k views

Why Java is a factor 2-3 slower than equivalent C++ program? [closed]

I know there is an opinion that programs written in Java and running under JVM as as fast as C++ programs, after introducing just-in-time (JIT). I see many cases when Java is terribly slow for simple ...
0
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1answer
59 views

How to write a new annotation that behaves precisely like an existing one?

Here is my use case. Suppose annotations did have inheritance and would automatically inherit the entire behaviour of the base class. Then I would do the following (note the two package statements): ...
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2answers
242 views

What is the rule for nested loop code?

I am new to programming and currently learning Java from Stanford free learning course. There was this assignment that I had trouble translating my algorithm into code. I feel like I have a ...
0
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0answers
21 views

What is determinism in computer science? [migrated]

I was asked if my computer program (in Java) was deterministic. I'm wondering how could it be not? There is no such thing as a non-deterministic Java program right? Even if I use a random number ...
1
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1answer
52 views

Language support for (syntactic) delegation in Java

Composition over inheritance is an old trend or even accepted state of the art in object oriented programming. It would be even easier to use in Java, if there were language support for delegation. ...
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0answers
11 views

Transparency of Pixel under mouse - Java JFrame [migrated]

I'm new to java and decided to make a program that : sets a point in the window when you left click. And then another point when you click again. And so on... Then it joins all the points up with ...
17
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7answers
3k views

Why is instance creation the way it is?

I've learned C# over the course of the past six months or so and am now delving into Java. My question is about instance creation (in either language, really) and it's more of: I wonder why they did ...
1
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1answer
80 views

Open closed principle vs abstraction leaking (Java enums)

In Java, an enum is not a plain replacement for a number (like in C/C++), but a family of objects which can have properties. For instance public enum Order { NAME("Ordering by name"), ...
12
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4answers
754 views

“Use map instead of class to represent data” -Rich Hickey

In this video by Rich Hickey, the Clojure creator, he advises to use map to represent data instead of using a class to represent it, as done in Java. I don't understand how it can be better, since how ...
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0answers
39 views

How to retrofit a program using log4j to use logstash instead?

I have a legacy java program that uses log4j. I would like to use the centralization features that logstash provides. How can I do this without modifying the original program? I don't have any ...
3
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1answer
181 views

How should I annotate, that a class is immutable in Java?

I recently stumbled upon how useful immutable objects are and that e.g. if you pass elements to a constructor and your class should be immutable, you have to copy these elements if they are not ...
3
votes
1answer
141 views

Does the JVM's Garbage Collector clean the entire JVM HotSpot memory (C-Heap, Java Heap and Permanent Generation space) or just Java Heap?

I know that the JVM has some JVM HotSpot memory which is further divided into three areas: Java Heap Permanent Generation Space Native Heap (C-Heap) I know that Java has automatic garbage ...
3
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2answers
242 views

Do wildcards in Java generics restrict or increase flexibility?

I have read many sources about wildcards and Java generics. Even though I have seen many explanations and answers, none of them seems correct. The question is very simple: Do wilcards in Java ...
1
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1answer
162 views

Most efficient way of searching very large strings of text in java

I have a question that I have been thinking about recently but I am still not sure of the answer(s) so I would like a broader opinion. Imagine the scenario where text strings of up to lets say ...
23
votes
4answers
3k views

Why doesn't Java have optimization for tail-recursion at all?

From what I have read: The reason is because it is not easy to determine which method will actually be called as we have inheritance. However, why doesn't Java at least have tail-recursion ...
0
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3answers
292 views

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 ...
0
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0answers
46 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 ...
0
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0answers
29 views

Does the zero that follows the fractional second part of a Jodatime formatted Date changes its Comparable order? [migrated]

Given two strings: a) 2013-05-02 02:11:05.24 b) 2013-05-02 02:11:05.240 Does joda time interpret these two to have the same Comparable order ? i.e. they are equivalent.
0
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0answers
4 views

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
vote
2answers
155 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 ...
2
votes
3answers
107 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, ...
1
vote
4answers
210 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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votes
0answers
52 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 . ...
0
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0answers
74 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 ...
14
votes
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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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
451 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? ...
4
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2answers
255 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 ...
0
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3answers
128 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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votes
1answer
92 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 ...