Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>The only harm that wildcard package imports can cause is an increased chance of namespace collisions if there are multiple classes of the same name in multiple packages.</p> <p>Say for example, I want to program to use the <code>ArrayList</code> class of the Java Collections Framework in an AWT application that uses a <code>List</code> GUI component to display information. For the sake of an example, let's suppose we have the following:</p> <pre><code>// 'ArrayList' from java.util ArrayList&lt;String&gt; strings = new ArrayList&lt;String&gt;(); // ... // 'List' from java.awt List listComponent = new List() </code></pre> <p>Now, in order to use the above, there would have to be an import for those two classes, minimally:</p> <pre><code>import java.awt.List; import java.util.ArrayList; </code></pre> <p>Now, if we were to use a wildcard in the package <code>import</code>, we'd have the following.</p> <pre><code>import java.awt.*; import java.util.*; </code></pre> <p>However, now we will have a problem!</p> <p>There is a <code>java.awt.List</code> class and a <code>java.util.List</code>, so referring to the <code>List</code> class would be ambiguous. One would have to refer to the <code>List</code> with a fully-qualified class name if we want to remove the ambiguity:</p> <pre><code>import java.awt.*; import java.util.*; ArrayList&lt;String&gt; strings = new ArrayList&lt;String&gt;(); // ... // 'List' from java.awt -- need to use a fully-qualified class name. java.awt.List listComponent = new java.awt.List() </code></pre> <p>Therefore, there are cases where using a wildcard package <code>import</code> can lead to problems.</p>
    singulars
    1. This table or related slice is empty.
    1. POEclipse/Java - is it harmful to import java.(namespace).*?
      singulars
      1. PTQuestion
    1. PTAnswer
    1. UScoobird
    1. UScoobird
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POEclipse/Java - is it harmful to import java.(namespace).*?
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COAre namespace collisions common enough in Java that you'd consider it to be a best practice not to import * namespaces?
      singulars
      1. PO
      1. USJames Cadd
    2. CO@James: Namespace collisions in Java are exceedingly common. Much more so than C#. The greater precision the better, in my opinion.
      singulars
      1. PO
      1. USAlohci
    3. CONot that often really; it depends on the APIs you're working with. But you need never write an import manually anyway, and Eclipse folds them away so you don't even see them, so I wouldn't worry about it! :)
      singulars
      1. PO
      1. USChristopher Orr
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload