All Questions
2,264
questions
652
votes
30
answers
528k
views
Can you find all classes in a package using reflection?
Is it possible to find all classes or interfaces in a given package? (Quickly looking at e.g. Package, it would seem like no.)
- 81.2k
544
votes
6
answers
262k
views
What is the convention for word separator in Java package names?
How should one separate words in package names? Which of the following are correct?
com.stackoverflow.my_package (Snake Case using underscore)
com.stackoverflow.my-package (Kebab Case using hyphens)
...
- 9,271
477
votes
8
answers
299k
views
javax vs java package
What's the rationale behind the javax package? What goes into java and what into javax?
I know a lot of enterprise-y packages are in javax, but so is Swing, the new date and time api (JSR-310) and ...
- 11.5k
306
votes
34
answers
1.8m
views
How can I solve "java.lang.NoClassDefFoundError"?
I've tried both the examples in Oracle's Java Tutorials. They both compile fine, but at run time, both come up with this error:
Exception in thread "main" java.lang.NoClassDefFoundError: ...
- 17.3k
232
votes
7
answers
173k
views
Are there best practices for (Java) package organization? [closed]
A little while ago, I saw a question answered here regarding the fine-grained organization of Java packages. For example, my.project.util, my.project.factory, my.project.service, etc.
Are there best ...
- 5,532
211
votes
3
answers
66k
views
How Do I Document Packages in Java?
In the Java APIs I can see Javadoc comments for packages.
How/where do I place Javadoc comments to document a package?
- 138k
186
votes
9
answers
79k
views
Making certain methods visible only to particular packages
I have two packages in my project: odp.proj and odp.proj.test. There are certain methods that I want to be visible only to the classes in these two packages. How can I do this?
If there is no concept ...
- 122k
156
votes
5
answers
62k
views
147
votes
7
answers
231k
views
Package structure for a Java project?
Whats the best practice for setting up package structures in a Java Web Application?
How would you setup your src, unit test code, etc?
- 3,989
128
votes
9
answers
186k
views
The import android.support cannot be resolved
I am trying to run the code provided HERE
I downloaded the code from their Github and imported into Android SDK, but it shows error at the lines
import android.support.v4.app.FragmentActivity;
...
- 7,145
109
votes
4
answers
186k
views
How to get current class name including package name in Java?
I'm working on a project and one requirement is if the 2nd argument for the main method starts with “/” (for linux) it should consider it as an absolute path (not a problem), but if it doesn't start ...
- 8,668
108
votes
3
answers
123k
views
Java JUnit: The method X is ambiguous for type Y
I had some tests working fine. Then, I moved it to a different package, and am now getting errors. Here is the code:
import static org.junit.Assert.*;
import java.util.HashSet;
import java.util.Map;
...
- 122k
99
votes
4
answers
91k
views
Naming conventions of composed package names
I want to create a package named form validator.
Is it better to write
form_validator,
formValidator or
formvalidator?
I want to mention that I want to avoid form.validator. And that form-validator ...
- 6,911
96
votes
14
answers
72k
views
Should interfaces be placed in a separate package? [closed]
I'm new to a team working on a rather large project, with lots of components and dependencies. For every component, there's an interfaces package where the exposed interfaces for that component are ...
- 11.1k
93
votes
6
answers
32k
views
Do unused import and objects have a performance impact?
Do the unused imports and unused objects in Java code create any performance impact?
Suppose an object is initialized and never used, what happens?
And what is the cost of unused imports?
- 3,107
93
votes
15
answers
35k
views
What strategy do you use for package naming in Java projects and why? [closed]
I thought about this awhile ago and it recently resurfaced as my shop is doing its first real Java web app.
As an intro, I see two main package naming strategies. (To be clear, I'm not referring to ...
- 12.8k
90
votes
14
answers
150k
views
Eclipse: The declared package does not match the expected package
I have a problem importing an external project. I go File -> Import... -> Existing Projects into Workspace, choose the folder where the project is located and everything is imported - but the package ...
- 1,153
87
votes
6
answers
69k
views
Java Package Vs Folder-Structure? what is the difference
I would like to know What are the difference between folder-structure and package used in Eclipse IDE for Java EE development.
When do we use which one and why?.
Whats should be the practice
...
- 1,629
81
votes
3
answers
52k
views
Why should java package name be lowercase?
Actually this is completely theoretic question. But it's interesting why java specification don't allow uppercase characters letters in package and cause write something like this:
com.mycompany....
- 1,041
72
votes
5
answers
81k
views
Simple statistics - Java packages for calculating mean, standard deviation, etc [closed]
Could you please suggest any simple Java statistics packages?
I don't necessarily need any of the advanced stuff. I was quite surprised that there does not appear to be a function to calculate the ...
- 20.7k
66
votes
3
answers
34k
views
Is the use of Java's default package a bad practice?
Is the use of Java's default package a bad practice?
- 11.1k
60
votes
5
answers
49k
views
Hyphenated company name in Java packages
Say you're working on the core module of the foo project for BarBaz Incorporated. Your code fragment might look like this:
package com.barbaz.foo.core;
import com.barbaz.foo.util;
What would the ...
- 82.2k
55
votes
14
answers
423k
views
Java Package Does Not Exist Error
So there's a folder /usr/share/stuff in the root directory
in stuff there are a bunch of java files with package org.name definitions at the top
I am running javac test.java where test.java is in a ...
- 6,701
54
votes
5
answers
26k
views
What's the convention for java package names without a domain association?
I can't find a Q/A on SO that answers my exact question, so I figure I'd post it and see what comes back.
As far as the naming convention goes for Java packages, I understand that it's supposed to be ...
- 48.6k
52
votes
4
answers
56k
views
How do I add package level annotations or edit package-info.java?
I'm trying to add package level annotations but I don't have a clue on how to do it. Examples are appreciated.
- 1,075
51
votes
2
answers
25k
views
Netbeans - is it possible to see project source folders in a tree (hierarchical) view, rather then a flat view?
I have some huge NetBeans projects with many packages, sub-packages, sub-sub-packages .etc, and it gets very confusing seeing all these package folders in the flat layout that NetBeans shows.. e.g. a....
- 1,565
51
votes
9
answers
24k
views
public methods in package-private classes
Does it make a difference to mark methods as public in package-private classes?
class SomePackagePrivateClass
{
void foo(); // package private method
public void bar(); // public ...
- 261k
51
votes
11
answers
54k
views
What is the purpose of defining a package in a Java file? [closed]
I am a newbie and just learned that if I define say
package my.first.group.here;
...
then the Java files that are in this package will be placed under my/first/group/here directory.
What is the ...
- 13.1k
51
votes
6
answers
33k
views
C++ Namespaces, comparison to Java packages
I've done a bunch of Java coding recently and have got used to very specific package naming systems, with deep nesting e.g. com.company.project.db. This works fine in Java, AS3/Flex and C#. I've seen ...
- 62.8k
50
votes
6
answers
119k
views
Why do package names often begin with "com" [duplicate]
Possible Duplicate:
Java packages com and org
I am a java developer. Nowadays I am learning struts and when reading a tutorial a curiosity intruded in my mind regarding
package com.something....
- 980
50
votes
6
answers
20k
views
What is the significance of the reverse domain name for java package structure
Why do we use reverse domain name like com.something. or org.something. structure for java packages?
I understand this brings in some sort of uniqueness, but why do we need this uniqueness?
- 5,815
49
votes
2
answers
136k
views
How to use org.apache.commons package?
On various web examples I see imports such as:
import org.apache.commons.net.ftp.FTPClient;
I don't understand how to use these, and the apache website is fairly unclear. How to I use these classes? ...
- 1,973
46
votes
9
answers
97k
views
How to wildcard include JAR files when compiling?
I have the following in a java file (MyRtmpClient.java):
import org.apache.mina.common.ByteBuffer;
and ByteBuffer is inside a JAR file (with the proper directory structure of course).
That jar file ...
javanewbie
45
votes
6
answers
16k
views
What is the clearest way to deprecate a package in Java?
I'm working on a new codebase and migrating the system to a new framework.
There are a number of packages that I would like to deprecate, just to make it very clear to other developers that ...
- 13.2k
44
votes
5
answers
9k
views
Is a Java package the equivalent of a .Net assembly?
I am a .Net developer starting Java development for Android and would like to know if it's correct to think of Java packages like .Net assemblies.
- 12.7k
43
votes
5
answers
119k
views
Running java in package from command line
I have read the previously posted questions. Some are vague and none solved my problem so I am forced to ask again.
I have two simple classes,
package One;
import One.Inner.MyFrame;
public class ...
- 695
43
votes
15
answers
179k
views
How to avoid Visual Studio Code warning: "[myfile].java is a non-project file, only syntax errors are reported"
I am running a build task in a Java project in Visual Studio Code.
The warning in the "PROBLEMS" tab:
[myfile].java is a non-project file, only syntax errors are reported
It refers to the ...
- 8,688
42
votes
13
answers
82k
views
How to run a .class file that is part of a package from cmd?
I keep getting errors when I make my .class part of a package and try to run it from cmd.
Here's the code that works after using javac and then java:
class HelloWorld {
public static void main(...
user2666594
42
votes
3
answers
43k
views
difference between protected and package-private access modifiers in Java? [duplicate]
I have seen various articles on differences between the protected and package private modifiers. One thing I found contradictory between these two posts
Isn't "package private" member ...
- 10.1k
40
votes
9
answers
37k
views
Java package cycle detection: how do I find the specific classes involved? [closed]
What tool would you recommend to detect Java package cyclic dependencies,
knowing that the goal is to list explicitly the specific classes involved in the detected 'across-packages cycle'?
I know ...
- 1.3m
39
votes
12
answers
48k
views
@RestController in other package doesn't work
I start with learning Spring and I create basic project which creates database, insert values and next print it in web browser.
My problem is that when I have RestController in the same package like ...
- 1,513
38
votes
4
answers
8k
views
"Cannot subclass the final class" error, but the class is not final [closed]
Here is my code:
package basic;
public abstract class Entity {}
package characters;
import basic.Entity;
public abstract class Character extends Entity {}
package player;
public class Player ...
- 621
38
votes
4
answers
3k
views
Why I am able to re-create java.lang package and classes?
I am just playing with package structure. And to my surprise I can bypass the default classes by creating my package and class name with that name.
For ex:
I created a package called java.lang and ...
- 122k
37
votes
6
answers
210k
views
Help with packages in java - import does not work
I'm a C++ developer - not a java developer, but have to get this code working...
I have 2 public classes that will be used by another product. I used the package directive in each of the java files. ...
- 20.3k
37
votes
2
answers
9k
views
How do I prevent Android Studio from automatically collapsing my packages in project navigation?
I have run into this annoyance over and over again and have been unable to find a solution or an answer here for it:
When I create a package in my application and then add a package within it, if I ...
- 1,677
37
votes
3
answers
11k
views
IntelliJ: Display .java extension in Packages View
I am pretty new to IntelliJ and I can't find an option to display all file extension in the packages view (in my case .java).
As you can see on the sceenshot it just says "Main" or "Controller" on ...
- 547
36
votes
10
answers
13k
views
How should I name packages if I don't have a domain associated with me? [closed]
So most Java resources when speaking of packages mention a com.yourcompany.project setup. However, I do not work for a company, and don't have a website. Are there any naming conventions that are ...
- 45.4k
34
votes
4
answers
21k
views
Package name is different than the folder structure but still Java code compiles
I am using Notepad++ to write my Java code and Command Prompt to compile and run it.
Following is my sample Java code,
package abraKadabra;
public class SuperClass{
protected int ...
- 2,391
34
votes
8
answers
6k
views
Too many imports are spamming my Java code
In my project I have a shapes package which has shapes I designed for my graphics program, e.g., Rectangle and Circle. I also have one or two more packages that have the same names as java.awt classes....
- 21.7k
34
votes
3
answers
48k
views
What is the default package in which my classes are put if I don't specify it?
Let's assume I have a file named Main.java with the following code:
public class Main {
public static void main(String[] args) {
System.out.println("Hello world");
}
}
Is it ...
- 104k