Questions tagged [java]

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.

Filter by
Sorted by
Tagged with
392
votes
35answers
625k views

Why isn't Java used for modern web application development? [closed]

As a professional Java programmer, I've been trying to understand - why the hate toward Java for modern web applications? I've noticed a trend that out of modern day web startups, a relatively small ...
295
votes
16answers
28k views

Grokking Java culture - why are things so heavy? What does it optimize for? [closed]

I used to code in Python a lot. Now, for work reasons, I code in Java. The projects I do are rather small, and possibly Python would work better, but there are valid non-engineering reasons to use ...
265
votes
14answers
110k 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 ...
262
votes
6answers
136k 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: ...
256
votes
7answers
291k views

What does the Spring framework do? Should I use it? Why or why not?

So, I'm starting a brand-new project in Java, and am considering using Spring. Why am I considering Spring? Because lots of people tell me I should use Spring! Seriously, any time I've tried to get ...
243
votes
12answers
302k views

How do you unit test private methods?

I am working on a java project. I am new to unit testing. What is the best way to unit test private methods in java classes?
212
votes
6answers
53k views

What exactly makes the Haskell type system so revered (vs say, Java)?

I'm starting to learn Haskell. I'm very new to it, and I am just reading through a couple of the online books to get my head around its basic constructs. One of the 'memes' that people familiar with ...
200
votes
40answers
20k views

My Dad is impatient with the pace of my learning to program. What do I do? [closed]

So my Dad bought me 5 books on programming (C++, Java, PHP, Javascript, Android) about a month ago. He's an architect and he knows NOTHING about programming. He bought me them because I told him ...
184
votes
16answers
133k views

When are Getters and Setters Justified

Getters and setters are often criticized as being not proper OO. On the other hand most OO code I've seen has extensive getters and setters. When are getters and setters justified? Do you try to ...
171
votes
10answers
24k views

Mono is frequently used to say “Yes, .NET is cross-platform”. How valid is that claim? [closed]

In What would you choose for your project between .NET and Java at this point in time? I say that I would consider the "Will you always deploy to Windows?" the single most important technical decision ...
163
votes
6answers
256k views

What is the point of using DTO (Data Transfer Objects)?

What is the point of using DTO and is it an out dated concept? I use POJOs in the view layer to transfer and persist data. Can these POJOs be considered as an alternative to DTOs?
145
votes
15answers
29k views

Why did memory-managed languages like Java, Javascript, and C# retain the `new` keyword?

The new keyword in languages like Java, Javascript, and C# creates a new instance of a class. This syntax seems to have been inherited from C++, where new is used specifically to allocate a new ...
138
votes
6answers
50k views

Why doesn't Java 8 include immutable collections?

The Java team has done a ton of great work removing barriers to functional programming in Java 8. In particular, the changes to the java.util Collections do a great job of chaining transformations ...
128
votes
4answers
104k views

Excessive use “final” keyword in Java [duplicate]

While I understand what the final keyword is used for in the context of classes and methods as well as the intent of its use for in regards to variables; however, the project I just started working on ...
127
votes
11answers
81k views

Why use Optional in Java 8+ instead of traditional null pointer checks?

We have recently moved to Java 8. Now, I see applications flooded with Optional objects. Before Java 8 (Style 1) Employee employee = employeeServive.getEmployee(); if(employee!=null){ System....
125
votes
5answers
63k views

In Java, should I use “final” for parameters and locals even when I don't have to?

Java allows marking variables (fields / locals / parameters) as final, to prevent re-assigning into them. I find it very useful with fields, as it helps me quickly see whether some attributes - or an ...
123
votes
6answers
85k views

What is the point of having every service class have an interface? [duplicate]

At the company I work at, every service class has a corresponding interface. Is this necessary? Notes: Most of these interfaces are only used by a single class We are not creating any sort of ...
119
votes
11answers
54k views

What backs up the claim that C++ can be faster than a JVM or CLR with JIT? [closed]

A reoccurring theme on SE I've noticed in many questions is the ongoing argument that C++ is faster and/or more efficient than higher level languages like Java. The counter-argument is that modern JVM ...
115
votes
12answers
17k views

Rationale to prefer local variables over instance variables?

The codebase I'm working on frequently uses instance variables to share data between various trivial methods. The original developer is adamant that this adheres to the best practices stated in the ...
115
votes
6answers
109k views

Why does the TRACE level exist, and when should I use it rather than DEBUG?

In Log4J, Slf4J and a couple other logging frameworks in Java, you have two "developper" level for logging: DEBUG TRACE I understand what DEBUG does, because the explanation is clear: The DEBUG ...
112
votes
13answers
19k views

Should we avoid language features that C++ has but Java doesn't?

Suppose I am limited to use C++ by the environment in the project. Is it good to prevent the use of some language features that C++ has but Java doesn't have (e.g.: multiple inheritance, operator ...
108
votes
6answers
94k views

Is it better to use assert or IllegalArgumentException for required method parameters?

In Java, which is more highly recommended, and why? Both types will throw exceptions, so in that regard handling them is the same. assert is slightly shorter, but I'm not sure how much that matters. ...
108
votes
5answers
91k views

Why were default and static methods added to interfaces in Java 8 when we already had abstract classes?

In Java 8, interfaces can contain implemented methods, static methods, and the so-called "default" methods (which the implementing classes do not need to override). In my (probably naive) view, there ...
106
votes
2answers
58k views

What is a “shaded” Java dependency?

JVM developer here. Lately I've seen banter on IRC chat rooms and even in my own office about so-called "shaded" Java libraries. The context of the use will be something like: "Such and so provides ...
105
votes
12answers
18k views

I've been told that Exceptions should only be used in exceptional cases. How do I know if my case is exceptional?

My specific case here is that the user can pass in a string into the application, the application parses it and assigns it to structured objects. Sometimes the user may type in something invalid. ...
102
votes
17answers
18k views

Is encapsulation still one of the elephants OOP stands on?

Encapsulation tells me to make all or almost all fields private and expose these by getters/setters. But now libraries such as Lombok appear which allow us to expose all private fields by one short ...
102
votes
5answers
45k 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 ...
102
votes
6answers
151k views

Stack and Heap memory in Java

As I understand, in Java, stack memory holds primitives and method invocations and heap memory is used to store objects. Suppose I have a class class A { int a ; String b; //...
101
votes
18answers
62k views

Is it poor programming practice to pass parameters as Objects? [duplicate]

So, we've got a guy who likes to write methods that take Objects as parameters, so they can be 'very flexible.' Then, internally, he either does direct casting, reflection or method overloading to ...
100
votes
4answers
68k views

How is a Java reference different from a C pointer?

C has pointers and Java has what is called references. They have some things in common in the sense that they all point to something. I know that pointers in C store the addresses they point to. Do ...
98
votes
10answers
14k views

Has / can anyone challenge Uncle Bob on his love of removing “useless braces”?

I hate referencing paywalled content, but this video shows exactly what I'm talking about. Precisely 12 minutes in Robert Martin looks at this: And says "One of my favorite things to do is getting ...
98
votes
9answers
26k views

Why is it hard to make a Java program 'appear native'?

Most Java applications don't look the same as C/C++ applications. Swing might have been designed on purpose to have a distincitve look, but based on what I've read, SWT for example tried to 'look ...
96
votes
3answers
82k views

What is the name of a function that takes no argument and returns nothing? [closed]

In Java 8's java.util.function package, we have: Function: Takes one argument, produces one result. Consumer: Takes one argument, produces nothing. Supplier: Takes no argument, produces one result. .....
93
votes
16answers
20k views

Do the young minds need to learn the pointer concepts?

Why did the C master Dennis Ritchie introduce pointers in C? And why did the other programming languages like VB.NET or Java or C# eliminate them? I have found some points in Google, and I want to ...
91
votes
17answers
17k views

Is imposing the same code format for all developers a good idea?

We are considering to impose a single standard code format in our project (auto format with save actions in Eclipse). The reason is that currently there is a big difference in the code formats used by ...
87
votes
10answers
44k views

How do you avoid getters and setters?

I'm having something of a hard time with designing classes in an oo way. I've read that objects expose their behavior, not their data; therefore, rather than using getter/setters to modify data, the ...
86
votes
6answers
18k views

Why are floats still part of the Java language when doubles are mostly recommended instead?

In every place I've looked, it says that double is superior to float in almost every way. float has been made obsolete by double in Java, so why is it still used? I program a lot with Libgdx, and ...
85
votes
11answers
12k 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 ...
85
votes
13answers
156k views

Why isn't Java more widely used for game development? [closed]

I'm not a game developer or anything, but I know that Java is not very widely used for game development. Java should be fast enough for most games, so where's the catch? I can think of some reasons: ...
83
votes
15answers
35k views

Why would it ever be possible for Java to be faster than C++?

Sometimes Java outperforms C++ in benchmarks. Of course, sometimes C++ outperforms. See the following links: http://keithlea.com/javabench/ http://blog.dhananjaynene.com/2008/07/performance-...
82
votes
12answers
25k views

What is the utility and advantage of getters & setters especially when they are merely used to read and assign values to properties of an object? [closed]

I’m still really new to learning to program. Just learning the syntax for a few programming languages at the moment. The courses I viewed for C# and Java touched only very briefly on getters & ...
82
votes
4answers
8k views

What's the difference between “to” and “as” method name prefixes? [closed]

What's the difference between "to" and "as" method name prefixes like toList(), asList(), etc... When to use which when designing a method?
82
votes
3answers
143k views

Is this an appropriate use of Mockito's reset method?

I have a private method in my test class that constructs a commonly used Bar object. The Bar constructor calls someMethod() method in my mocked object: private @Mock Foo mockedObject; // My mocked ...
80
votes
11answers
33k views

Why is String immutable in Java?

I couldn't understand the reason of it. I always use String class like other developers, but when I modify the value of it, new instance of String created. What might be the reason of immutability ...
79
votes
11answers
24k views

Why aren't Java objects deleted immediately after they are no longer referenced?

In Java, as soon as an object no longer has any references, it becomes eligible for deletion, but the JVM decides when the object is actually deleted. To use Objective-C terminology, all Java ...
79
votes
10answers
94k views

How many lines per class is too many in Java? [closed]

In your experience, what is a useful rule of thumb for how many lines of code are too many for one class in Java? To be clear, I know that number of lines is not even close to the real standard to ...
79
votes
7answers
156k views

Why declare final variables inside methods? [duplicate]

Studying some classes of Android, I realized that most of the variables of methods are declared as final. Example code taken from the class android.widget.ListView: /** * @return Whether the list ...
79
votes
13answers
82k views

Is it good practice to catch a checked exception and throw a RuntimeException?

I read some code of a colleague and found that he often catches various exceptions and then always throws a 'RuntimeException' instead. I always thought this is very bad practice. Am I wrong?
78
votes
3answers
26k views

What does “GPL with classpath exception” mean in practice?

Oracle seems to license all their Java-related open source code under the GPL with a classpath exception. From what I understand, this seems to allow to combine these libraries with your own code into ...
75
votes
6answers
146k views

Service layer vs DAO — Why both?

I have been working with SpringMVC, Hibernate, and some databases in a java web application example. There are a few different ones that do this, but this Spring 3 and hibernate integration tutorial ...

1
2 3 4 5
95