I also like to use [**UCDetector**][1]:

![screenshot][2]

&gt; UCDetector (Unecessary Code Detector) is a Open Source eclipse PlugIn Tool to find unecessary (dead) public java code. It also tries to make code final, protected or private.

Bonus: it can also find cyclic dependencies between classes 

(also a [number of other tools][3] -- including Findbugs -- knows how do do that too)

----

**Caveat**: [Cid][4] mentions [in the comments][5]:

&gt; UCDetector shall not work if there are interface implementations which will be known only at runtime.  
It incorrectly marks the implementation classes as unused.

----

Update 2017: static code analysis has evolved quite a bit in 8 years.  
Using [SonarLint for Eclipse][6], you can use the the latest [SonarJava 4.6 plugin][7] to analyze your code.  
It will [find dead code][8].


  [1]: http://www.ucdetector.org/index.html
  [2]: http://i.stack.imgur.com/NBA01.png
  [3]: https://stackoverflow.com/questions/62276/java-package-cycle-detection-how-to-find-the-specific-classes-involved
  [4]: https://stackoverflow.com/users/966078/cid
  [5]: https://stackoverflow.com/questions/665563/find-unused-classes-in-a-java-eclipse-project/665778#comment16413500_665778
  [6]: https://www.sonarlint.org/eclipse/
  [7]: https://docs.sonarqube.org/display/PLUG/SonarJava
  [8]: https://jira.sonarsource.com/browse/RSPEC-901

**[ProGuard][1]** can be used to print a report of unused classes/methods. It&#39;s a pain to supply all the dependent jars to it, though.

These options list unused classes, fields, and methods in the application mypackage.MyApplication:

    -injars      in.jar
    -libraryjars &lt;java.home&gt;/lib/rt.jar
    
    -dontoptimize
    -dontobfuscate
    -dontpreverify
    -printusage
    
    -keep public class mypackage.MyApplication {
        public static void main(java.lang.String[]);
    }


  [1]: http://proguard.sourceforge.net/#manual/examples.html

Just use Analyze | Inspect Code with appropriate inspection enabled (Unused declaration under Declaration redundancy group).

Using IntelliJ 11 CE you can now &quot;Analyze | Run Inspection by Name ... | Unused declaration&quot;

Apart from the google/bigtable scenario, when shouldn&#39;t you use a relational database? Why not, and what should you use? (did you learn &#39;the hard way&#39;?) 


When shouldn&#39;t you use a relational database?

So let&#39;s say I wanna make a dictionary. We&#39;ll call it `d`. But there are multiple ways to initialize a dictionary in Python! For example, I could do this:

    d = {&#39;hash&#39;: &#39;bang&#39;, &#39;slash&#39;: &#39;dot&#39;}

Or I could do this:

    d = dict(hash=&#39;bang&#39;, slash=&#39;dot&#39;)

Or this, curiously:

    d = dict({&#39;hash&#39;: &#39;bang&#39;, &#39;slash&#39;: &#39;dot&#39;})

Or this:
    
    d = dict([[&#39;hash&#39;, &#39;bang&#39;], [&#39;slash&#39;, &#39;dot&#39;]])

And a whole other multitude of ways with the `dict()` function. So obviously one of the things `dict()` provides is flexibility in syntax and initialization. But that&#39;s not what I&#39;m asking about.

Say I were to make `d` just an empty dictionary. What goes on behind the scenes of the Python interpreter when I do `d = {}` versus `d = dict()`? Is it simply two ways to do the same thing? Does using `{}` have the &lt;i&gt;additional&lt;/i&gt; call of `dict()`? Does one have (even negligible) more overhead than the other? While the question is really completely unimportant, it&#39;s a curiosity I would love to have answered.

What&#39;s the difference between dict() and {}?

I have a large Eclipse project in which there exist several classes which, although they ceased to be used anywhere, were never marked @Deprecated.

How can I easily find all of these?

Find unused classes in a Java Eclipse project

<p>I have a large Eclipse project in which there exist several classes which, although they ceased to be used anywhere, were never marked @Deprecated.</p>
<p>How can I easily find all of these?</p>


Is there any utility for deep cloning for java collections:

 - Arrays
 - Lists
 - Maps

NOTE: prefer some solution without usage of serialization, but with use of Object.clone() method. I can be sure that my custom object will implement clone() method and will use only java-standard classes that are cloneable...

Deep clone utility recommendation

We want to split a working application in two different `.war` files in order to be able to update one app without affecting the other. Each webapp will have different a UI, different users and different deploy schedule. 

The easiest path seems to be sharing the same session, so if app A set `session.setAttribute(&quot;foo&quot;, &quot;bar&quot;)` app B will be able to see it.

Is there a way to share the `HttpSession` state for both apps in the same Tomcat instance?

Our app is running on a dedicated Tomcat 5.5, there are no other apps running on the same tomcat instance, so any security concerns regarding the session sharing are not a problem. We&#39;re running multiple Tomcat instances, but the balancer is using sticky sessions.

If it&#39;s not possible or this &lt;em&gt;session sharing&lt;/em&gt; is a really bad idea please leave a comment.

Any way to share session state between different applications in tomcat?

In my Android app, I always get VerifyErrors! And I cannot figure out why. Whenever I include a external JAR, I always get VerifyErrors when I try to launch my app (except for once, when I included Apache Log4j.) 

I usually get around this by taking the source of the library and adding it to my project, but I am trying to put the [GData client library][1].

I can get this in source, but it&#39;s dependencies (mail.jar, activation.jar, servlet-api.jar) I cannot, so I get verify errors. I would like to get to the root of this problem once and for all. I looked on the internet, but they all seem to talk about incomplete class files? which I do not know of.


  [1]: http://code.google.com/p/gdata-java-client/

Android java.lang.VerifyError?

What is the clearest way to comma-delimit a list in Java?

I know several ways of doing it, but I&#39;m wondering what the best way is (where &quot;best&quot; means clearest and/or shortest, not the most efficient.

I have a list and I want to loop over it, printing each value.  I want to print a comma between each item, but not after the last one (nor before the first one).

    List --&gt; Item ( , Item ) *
    List --&gt; ( Item , ) * Item


Sample solution 1:

    boolean isFirst = true;
    for (Item i : list) {
      if (isFirst) {
        System.out.print(i);        // no comma
        isFirst = false;
      } else {
        System.out.print(&quot;, &quot;+i);   // comma
      }
    }

Sample solution 2 - create a sublist:

    if (list.size()&gt;0) {
      System.out.print(list.get(0));   // no comma
      List theRest = list.subList(1, list.size());
      for (Item i : theRest) {
        System.out.print(&quot;, &quot;+i);   // comma
      }
    }

Sample solution 3:

      Iterator&lt;Item&gt; i = list.iterator();
      if (i.hasNext()) {
        System.out.print(i.next());
        while (i.hasNext())
          System.out.print(&quot;, &quot;+i.next());
      }


These treat the first item specially; one could instead treat the last one specially.

Incidentally, here is how `List` `toString` *is* implemented (it&#39;s inherited from `AbstractCollection`), in Java 1.6:

    public String toString() {
        Iterator&lt;E&gt; i = iterator();
        if (! i.hasNext())
            return &quot;[]&quot;;
    
        StringBuilder sb = new StringBuilder();
        sb.append(&#39;[&#39;);
        for (;;) {
            E e = i.next();
            sb.append(e == this ? &quot;(this Collection)&quot; : e);
            if (! i.hasNext())
                return sb.append(&#39;]&#39;).toString();
            sb.append(&quot;, &quot;);
        }
    }

It exits the loop early to avoid the comma after the last item.  BTW: this is the first time I recall seeing &quot;(this Collection)&quot;; here&#39;s code to provoke it:

    List l = new LinkedList();
    l.add(l);
    System.out.println(l);


I welcome any solution, even if they use unexpected libraries (regexp?); and also solutions in languages other than Java (e.g. I think Python/Ruby have an *intersperse* function - how is *that* implemented?).

*Clarification*: by libraries, I mean the standard Java libraries.  For other libraries, I consider them with other languages, and interested to know how they&#39;re implemented.

*EDIT* toolkit mentioned a similar question: https://stackoverflow.com/questions/285523/last-iteration-of-for-loop-in-java

And another:
https://stackoverflow.com/questions/156650/does-the-last-element-in-a-loop-deserve-a-separate-treatment


The simplest way to comma-delimit a list?

How do you kill a `java.lang.Thread` in Java?

How do you kill a Thread in Java?

The list of jars just takes up too much space. Can I collapse it or hide it?

Remove project .jars from project explorer view in Eclipse

I am moving my Subversion repository from one machine to another.  I have a few scattered working copies on various machines, and I have found that I can easily switch the working copies from the old server to the new one with the following command:

    svn --relocate svn://oldServer/repo svn://newServer/repo

However, on one of my machines, I use Eclipse with Subclipse, and I don&#39;t like to use command-line SVN on my Eclipse projects.  My question is whether it is possible to switch SVN repositories from within Eclipse using either Subclipse or Subversive.

Can I switch SVN repositories from Eclipse?

I&#39;ve got a small project which, when run in the Eclipse debugger, always seems to stop in FileInputStream.class line 106, where files are opened.  There are no breakpoints set, but Eclipse behaves exactly as if I have a breakpoint here.  If I clear all breakpoints, it still happens.

I have a second much-larger project in the same Eclipse workspace which does not suffer from this problem.

I just moved the smaller project off of my old Linux machine, where I developed it in Europa Eclipse and had this problem, onto my new Windows machine, where I continue to see the problem in Ganymede Eclipse.  The problem persists across operating systems and across Eclipse versions, yet apparently not across projects.  I don&#39;t get it!  I grepped through every file in this project&#39;s directory and couldn&#39;t find anything that might be a file somehow directing Eclipse to stop in FileInputStream.

**Further info**: the apparent breakpoint is actually not for line 106 of FileInputStream; it appears to be an Exception breakpoint for FileNotFoundException, being thrown from native code called from that line in FileInputStream.  But again, I don&#39;t appear to have any breakpoints set at all.  Are Exception breakpoints defined somewhere else?

Why does my Eclipse project have phantom debugger breakpoints?

Is there a way to reload an Android application in the emulator without closing the emulator, saving any code changes, and running the emulator again?  If I make even a simple change to the layout, it takes about 30 seconds by time I run it in Eclipse and Android &quot;boots&quot;, and I can unlock the emulator to run the application.  Is there any way to shorten this time when making changes, or is it something I just have to deal with?

Reload Android application in emulator without restarting emulator in Eclipse?

How can I change eclipse&#39;s Internal Browser from IE to Firefox on Windows XP?

To be more specific I need to change the Internal Browser instead of adding the External Browser through Preferences -&gt; General -&gt; Web Browser.

How can I change eclipse&#39;s Internal Browser from IE to Firefox on Windows XP?

I&#39;m interested mostly in C++ and method/class name/signature automatic changes.

How can I refactor C++ source code using emacs?

So you&#39;ve got some legacy code lying around in a fairly hefty project. How can you find and delete dead functions?

I&#39;ve seen these two references: [Find unused code][1] and [Tool to find unused functions in php project][2], but they seem specific to C# and PHP, respectively.

Is there a Python tool that&#39;ll help you find functions that aren&#39;t referenced anywhere else in the source code (notwithstanding reflection/etc.)?


  [1]: https://stackoverflow.com/questions/245963
  [2]: https://stackoverflow.com/questions/11532


How can you find unused functions in Python code?

I&#39;ve been playing around with measuring the cyclomatic complexity of a big code base.

Cyclomatic complexity is the number of linearly independent paths through a program&#39;s source code and there are lots of free tools for your language of choice.

The results are interesting but not surprising.   That is, the parts I know to be the hairiest were in fact the most complex (with a rating of &gt; 50).  But what I am finding useful is that a concrete &quot;badness&quot; number is assigned to each method as something I can point to when deciding where to start refactoring.

Do you use cyclomatic complexity?  What&#39;s the most complex bit of code you found? 

Do you find cyclomatic complexity a useful measure?

JSLint (with the onevar flag turned on) is flagging some javascript code that I have with the following:

&lt;pre&gt;Problem at line 5 character 15: Too many var statements.&lt;/pre&gt;

I am happy to fix these errors, but I&#39;d like to know, am I doing it for performance or because it is just a bad practice and has a greater potential to introduce bugs in my javascript code.  What is the reason behind the onevar flag?

I did look at the JSLint docs for the [var keyword][1] but it doesn&#39;t specifically talk about why multiple var statements in the same function are bad.

Here is an attempt at an example.  Explain how the code will benefit from only having 1 var statement:

    function Test(arg) {
       var x = arg + 1,
           y = cache.GetItem(&#39;xyz&#39;);
       if (y !== null) {
          // This is what would cause the warning in JSLint
          var request = ajaxPost(/* Parameters here */);
          
       }
    }

  [1]: http://www.jslint.com/lint.html#var



What is the reason behind JSLint saying there are &quot;too many var statements&quot;

I want to refactor a big Python function into smaller ones. For example, consider this following code snippet:

    x = x1 + x2 + x3 + x4 + x5 + x6 + x7 + x8 + x9

Of course, this is a trivial example. In practice, the code is more complex. My point is that it contains many local-scope variables that would have to be passed to the extracted function, which could look like:

    def mysum(x1, x2, x3, x4, x5, x6, x7, x8, x9):
        x = x1 + x2 + x3 + x4 + x5 + x6 + x7 + x8 + x9
        return x

The problem is that Pylint would trigger a warning about too many arguments.

I could avoid the warning by doing something like:

    def mysum(d):
        x1 = d[&#39;x1&#39;]
        x2 = d[&#39;x2&#39;]
        ...
        x9 = d[&#39;x9&#39;]
        x = x1 + x2 + x3 + x4 + x5 + x6 + x7 + x8 + x9
        return x

    def mybigfunction():
        ...
        d = {}
        d[&#39;x1&#39;] = x1
        ...
        d[&#39;x9&#39;] = x9
        x = mysum(d)

but this approach loos ugly to me. It requires writing a lot of code that is even redundant.

Is there a better way to do it?





Content Type	Original Author	Original Content on Stackoverflow
Question	jjujuma	View Question on Stackoverflow
Solution 1 - Java	VonC	View Answer on Stackoverflow
Solution 2 - Java	rustyx	View Answer on Stackoverflow
Solution 3 - Java	Hasan Jamshaid	View Answer on Stackoverflow

Find unused classes in a Java Eclipse project

Java Problem Overview

Java Solutions

Solution 1 - Java

Solution 2 - Java

Solution 3 - Java

What's the difference between dict() and {}?

When shouldn't you use a relational database?

Attributions