`package-info.java`: &quot;This file is new in JDK 5.0, and is preferred over package.html.&quot;—[*javadoc - The Java API Documentation Generator*][1]

Addendum: The big difference seems to be _package annotations_. There&#39;s a little more in the way of rationale in [*7.4 Package Declarations*][2].

Addendum: The annotation feature is also mentioned [here][3] and [here][4].

Addendum: See also [*What’s `package-info.java` for?*][5].


 [1]: https://docs.oracle.com/javase/8/docs/technotes/tools/unix/javadoc.html#packagecomment
 [2]: https://docs.oracle.com/javase/specs/jls/se8/html/jls-7.html#jls-7.4
 [3]: https://blogs.oracle.com/darcy/entry/javadoc_tip_prefer_package_info
 [4]: http://tech.puredanger.com/2007/02/28/package-annotations/
 [5]: https://www.intertech.com/Blog/whats-package-info-java-for/

I do most of my programming in Python 3.x on Windows 7, but now I need to use the Python Imaging Library (PIL), ImageMagick, and wxPython, all of which require Python 2.x.

Can I have both Python 2.x and Python 3.x installed in Windows 7? When I run a script, how would I &quot;choose&quot; which version of Python should run it? Will the aforementioned programs be able to handle multiple versions of Python installed at once? I have searched for hours and hours for how to do this to no avail.

Thanks.

How to install both Python 2.x and Python 3.x in Windows

Is it possible to have a function with two returns like this:

    function test($testvar)
    {
      // Do something

      return $var1;
      return $var2;
    }

If so, how would I be able to get each return separately?





Multiple returns from a function

When trying to create package level Javadoc comments, whats the preferred method? What do you do?

**package-info.java**

 - Pros
  - Newer
 - Cons
  - Abuse of a class - Classes are for code, not for only comments

**package.html**

 - Pros
  - HTML extension means its not code
  - Syntax highlighting in IDE&#39;s/text editors
 - Cons
  - None?

---

For me, I&#39;ve always used Package.html. But I&#39;m wondering if its the correct choice. 


Javadoc: package.html or package-info.java

When trying to create package level Javadoc comments, whats the preferred method? What do you do?
package-info.java
<ul>
<li>Pros</li>
<li>Newer</li>
<li>Cons</li>
<li>Abuse of a class - Classes are for code, not for only comments</li>
</ul>
package.html
<ul>
<li>Pros</li>
<li>HTML extension means its not code</li>
<li>Syntax highlighting in IDE's/text editors</li>
<li>Cons</li>
<li>None?</li>
</ul>
<hr>
For me, I've always used Package.html. But I'm wondering if its the correct choice.

I just know that the non-primitives (the objects) go on the heap, and methods go on the stack, but what about the primitive variables?

**--update**

Based on the answers, I could say the heap can have a new stack and heap for a given object? Given that the object will have primitive and reference variables..?

Do Java primitives go on the Stack or the Heap?

I believe that we are all know that  setUp (@Before) will execute before any test method and tearDown(@After) will execute after test method.

Also we know that Junit will create one instance of Test **per test method**. 

my question is that can we just move  setUp method content to class Constructor and remove setUp method? is there any specific reason to keep setUp method?

setUp/tearDown (@Before/@After) why we need them in JUnit?

I&#39;m trying to send an email using Java:

    import java.util.*;
    import javax.mail.*;
    import javax.mail.internet.*;
    import javax.activation.*;
    
    public class SendEmail {
    
       public static void main(String [] args) {
          
          // Recipient&#39;s email ID needs to be mentioned.
          String to = &quot;abcd@gmail.com&quot;;
    
          // Sender&#39;s email ID needs to be mentioned
          String from = &quot;web@gmail.com&quot;;
    
          // Assuming you are sending email from localhost
          String host = &quot;localhost&quot;;
    
          // Get system properties
          Properties properties = System.getProperties();
    
          // Setup mail server
          properties.setProperty(&quot;mail.smtp.host&quot;, host);
    
          // Get the default Session object.
          Session session = Session.getDefaultInstance(properties);
    
          try{
             // Create a default MimeMessage object.
             MimeMessage message = new MimeMessage(session);
    
             // Set From: header field of the header.
             message.setFrom(new InternetAddress(from));
    
             // Set To: header field of the header.
             message.addRecipient(Message.RecipientType.TO,
                                      new InternetAddress(to));
    
             // Set Subject: header field
             message.setSubject(&quot;This is the Subject Line!&quot;);
    
             // Now set the actual message
             message.setText(&quot;This is actual message&quot;);
    
             // Send message
             Transport.send(message);
             System.out.println(&quot;Sent message successfully....&quot;);
          }catch (MessagingException mex) {
             mex.printStackTrace();
          }
       }
    }

I am getting the error :

    javax.mail.MessagingException: Could not connect to SMTP host: localhost, port: 25;
      nested exception is:java.net.ConnectException: Connection refused: connect
            at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1706)
            at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:525)

Will this code work to send email?





Send email using java

I use `GZIPOutputStream` or `ZIPOutputStream` to compress a String (my `string.length()` is less than 20), but the compressed result is longer than the original string.

On some site, I found some friends said that this is because my original string is too short, `GZIPOutputStream` can be used to compress longer strings.

so, can somebody give me a help to compress a String?

My function is like:

    String compress(String original) throws Exception {

    }


Update:

    import java.io.ByteArrayOutputStream;
    import java.io.IOException;
    import java.util.zip.GZIPOutputStream;
    import java.util.zip.*;


    //ZipUtil 
    public class ZipUtil {
        public static String compress(String str) {
            if (str == null || str.length() == 0) {
                return str;
            }

            ByteArrayOutputStream out = new ByteArrayOutputStream();
            GZIPOutputStream gzip = new GZIPOutputStream(out);
            gzip.write(str.getBytes());
            gzip.close();
            return out.toString(&quot;ISO-8859-1&quot;);
        }

        public static void main(String[] args) throws IOException {
	        String string = &quot;admin&quot;;
            System.out.println(&quot;after compress:&quot;);
            System.out.println(ZipUtil.compress(string));
        }
    }

 


 The result is :

![alt text][1]


  [1]: http://i.stack.imgur.com/NUYbH.jpg

How to compress a String in Java?

I am trying to match a multi line text using java. When I use the `Pattern` class with the `Pattern.MULTILINE` modifier, I am able to match, but I am not able to do so with `(?m).`

The same pattern with `(?m)` and using `String.matches` does not seem to work.

I am sure I am missing something, but no idea what. Am not very good at regular expressions.

This is what I tried

    String test = &quot;User Comments: This is \t a\ta \n test \n\n message \n&quot;;
    		
    String pattern1 = &quot;User Comments: (\\W)*(\\S)*&quot;;
    Pattern p = Pattern.compile(pattern1, Pattern.MULTILINE);
    System.out.println(p.matcher(test).find());  //true
    
    String pattern2 = &quot;(?m)User Comments: (\\W)*(\\S)*&quot;;
    System.out.println(test.matches(pattern2));  //false - why?



Match multiline text using regular expression

I&#39;d like to know how to setup IntelliJ to point to the JDK documentation so the documentation popups that display during code completion will show me what the function I&#39;m looking at is going to do. For some reason IntelliJ isn&#39;t able to find the JavaDocs by default.

I&#39;m also not 100% sure that the documentation is installed with the JDK that&#39;s installed with the OS. I don&#39;t see them in /System/Library/Frameworks/JavaVM.framework/ but I may be looking in the wrong place. If it&#39;s not included, I&#39;d also like to know what needs to be downloaded and where it needs to be installed to get the JavaDocs for the JDK to show up in IntelliJ.

JDK documentation in IntelliJ IDEA on Mac OS X

I have written Javadoc style comments like this in my project&#39;s code:

    /**
     * Description...
     *
     * @param ...
     * @return .....
     */

How can I generate Javadoc HTML files using the Eclipse IDE?

How to generate Javadoc HTML files in Eclipse?

Can anybody show me how to generate Javadoc from command line?

My project contains the package `com.test` and I want to put the generated documentation in files located in a specific folder like this: `C:/javadoc/test`.

How to generate Javadoc from command line

I have downloaded Java API documentation from http://www.oracle.com/technetwork/java/javase/downloads/index.html#docs and have supposedly attached it to Eclipse using the 

&gt; Window-&gt;Preferences-&gt;Java-&gt;Installed
&gt; JREs-&gt;Edit-&gt;&quot;Select rt.jar&quot;-&gt;Javadoc
&gt; Location

And the location has been accepted and &quot;Validates&quot; just fine. However, for the life of me, I can&#39;t get Eclipse to show the Javadocs in the tooltip whene I hover over an item (for example in the declaration of an ArrayList). I have also restarted Eclipse in attempts to get it to work

What am I doing wrong?

How do I add the Java API documentation to Eclipse?

When do I use `@see` when dealing with JavaDocs? What is its usage?

For example if `MethodA` calls `MethodB` then do I have to put `@see` in `MethodB`&#39;s javadoc and reference `MethodA` because that is what called it, or do I have to put a reference to `MethodB` from `MethodA` because it&#39;s calling it. I&#39;ve read the stuff about `@see` on the Oracle website and it seems to me to be incredibly vague, it says it means &quot;see also&quot; but not really what that means!

Content Type	Original Author	Original Content on Stackoverflow
Question	TheLQ	View Question on Stackoverflow
Solution 1 - Java	trashgod	View Answer on Stackoverflow

Javadoc: package.html or package-info.java

Java Problem Overview

Java Solutions

Solution 1 - Java

Multiple returns from a function

How to install both Python 2.x and Python 3.x in Windows

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