You can use the Display view to execute arbitrary code, access it via:

&gt; window-&gt;Show View-&gt;Display

then type the code you want to execute (you can use `CTRL+SPACE` for autocomplete).

to execute the code, select it then: 

&gt; CTRL+SHIFT+D

That should execute the code based on the breakpoint you&#39;ve hit.

[![alt text][1]][1]
&lt;!-- source: http://i39.tinypic.com/1z4jsd0.gif --&gt;


Note: As of 2018, Display View has been renamed to [Debug Shell View][2].


  [1]: https://i.stack.imgur.com/sXKyU.gif
  [2]: https://help.eclipse.org/photon/index.jsp?topic=%2Forg.eclipse.jdt.doc.user%2Freference%2Fviews%2Fdisplay%2Fref-debug_shell_view.htm

Eclipse has it indeed. Window-&gt;Show View-&gt;Interactive Console. Note that you can also execute expressions in the Watch view (e.g. result=false, exception.printStackTrace() etc.).

I&#39;ve read about 10 different questions on when and how to override `GetHashCode` but there&#39;s still something I don&#39;t quite get.  Most implementations of `GetHashCode` are based on the hash codes of the fields of the object, but it&#39;s been cited that the value of `GetHashCode` should never change over the lifetime of the object.  How does that work if the fields that it&#39;s based on are mutable?  Also what if I do want dictionary lookups etc to be based on reference equality not my overridden `Equals`?  

I&#39;m primarily overriding `Equals` for the ease of unit testing my serialization code which I assume serializing and deserializing (to XML in my case) kills the reference equality so I want to make sure at least it&#39;s correct by value equality.  Is this bad practice to override `Equals` in this case?  Basically in most of the executing code I want reference equality and I always use `==` and I&#39;m not overriding that.  Should I just create a new method `ValueEquals` or something instead of overriding `Equals`?  I used to assume that the framework always uses `==` and not `Equals` to compare things and so I thought it was safe to override `Equals` since it seemed to me like its purpose was for if you want to have a 2nd definition of equality that&#39;s different from the `==` operator.  From reading several other questions though it seems that&#39;s not the case.


**EDIT:**

It seems my intentions were unclear, what I mean is that 99% of the time I want plain old reference equality, default behavior, no surprises.  For very rare cases I want to have value equality, and I want to explicitly request value equality by using `.Equals` instead of `==`.  

When I do this the compiler recommends I override `GetHashCode` as well, and that&#39;s how this question came up.  It seemed like there&#39;s contradicting goals for `GetHashCode` when applied to mutable objects, those being:

 1. If `a.Equals(b)` then `a.GetHashCode()` should `== b.GetHashCode()`.
 2. The value of `a.GetHashCode()` should never change for the lifetime of `a`.

These seem naturally contradicting when a mutable object, because if the state of the object changes, we expect the value of `.Equals()` to change, which means that `GetHashCode` should change to match the change in `.Equals()`, but `GetHashCode` should not change.

Why does there seem to be this contradiction?  Are these recommendations not meant to apply to mutable objects?  Probably assumed, but might be worth mentioning I&#39;m referring to classes not structs.

**Resolution:**

I&#39;m marking JaredPar as accepted, but mainly for the comments interaction.  To sum up what I&#39;ve learned from this is that the only way to achieve all goals and to avoid possible quirky behavior in edge cases is to only override `Equals` and `GetHashCode` based on immutable fields, or implement `IEquatable`.  This kind of seems to diminish the usefulness of overriding `Equals` for reference types, as from what I&#39;ve seen most reference types usually have no immutable fields unless they&#39;re stored in a relational database to identify them with their primary keys.

Overriding GetHashCode for mutable objects?

How can I have a 64-bit integer in PHP?

It seems like it is not by a config file, but rather it might be a compile-time option, and it depends on the platform.



How can I have a 64-bit integer in PHP?

In most programming languages I&#39;ve used, when debugging, when I hit a breakpoint, I have the ability to execute arbitrary code (whatever I type into the console after the breakpoint has been hit).

How do I do this in Eclipse?  The debugging mode has, by default, a display console, but no interactive console (into which I can input Java code for immediate execution)



In eclipse, while debugging, how do I access the interactive-top-level (a.ka. the &quot;display console&quot;)?

<p>In most programming languages I've used, when debugging, when I hit a breakpoint, I have the ability to execute arbitrary code (whatever I type into the console after the breakpoint has been hit).</p>
<p>How do I do this in Eclipse?  The debugging mode has, by default, a display console, but no interactive console (into which I can input Java code for immediate execution)</p>


Can Java properties file reference other properties file?

    ## define a default directory for Input files  
    dir.default=/home/data/in/
    
    dir.proj1=${dir.default}p1
    dir.proj2=${dir.default}p2
    dir.proj3=${dir.default}p3

Is this possible?


How to reference another property in java.util.Properties?

The `java.util.Properties` class is meant to represent a map where the keys and values are both Strings. This is because `Properties` objects are used to read `.properties` files, which are text files.

So, why in Java 5 did they retrofit this class to implement `Map&lt;Object,Object&gt;` and not `Map&lt;String,String&gt;`? 


The &lt;a href=&quot;http://java.sun.com/j2se/1.5.0/docs/api/&quot;&gt;javadoc&lt;/a&gt; states:

&gt; Because Properties inherits from Hashtable, the put and putAll methods can be applied to a Properties object. Their use is strongly discouraged as they allow the caller to insert entries whose keys or values are not Strings. The setProperty method should be used instead. If the store or save method is called on a &quot;compromised&quot; Properties object that contains a non-String key or value, the call will fail.

Since the keys and values are both supposed to be Strings then why not enforce that statically by using the proper generic type?

I guess making `Properties` implement `Map&lt;String,String&gt;` would not be fully backward compatible with code written for pre-Java 5. If you have older code that sticks non-strings into a Properties object then that code would no longer compile with Java 5. But... isn&#39;t that a good thing? Isn&#39;t the whole point of generics to catch such type errors at compile time?

Why does java.util.Properties implement Map&lt;Object,Object&gt; and not Map&lt;String,String&gt;

I am using Java 6 and am trying to create an `HttpsURLConnection` against a remote server, using a client certificate.  
The server is using an selfsigned root certificate, and requires that a password-protected client certificate is presented. I&#39;ve added the server root certificate and the client certificate to a default java keystore which I found in `/System/Library/Frameworks/JavaVM.framework/Versions/1.6.0/Home/lib/security/cacerts` (OSX 10.5).
The name of the keystore file seems to suggest that the client certificate is not supposed to go in there?

Anyway, adding the root certificate to this store solved the infamous `javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed&#39; problem.`

However, I&#39;m now stuck on how to use the client certificate. I&#39;ve tried two approaches and neither gets me anywhere.   
First, and preferred, try:

    SSLSocketFactory sslsocketfactory = (SSLSocketFactory) SSLSocketFactory.getDefault();
    URL url = new URL(&quot;https://somehost.dk:3049&quot;);
    HttpsURLConnection conn = (HttpsURLConnection)url.openConnection();
    conn.setSSLSocketFactory(sslsocketfactory);
    InputStream inputstream = conn.getInputStream();
    // The last line fails, and gives:
    // javax.net.ssl.SSLHandshakeException: Received fatal alert: handshake_failure

I&#39;ve tried skipping the HttpsURLConnection class (not ideal since I want to talk HTTP with the server), and do this instead:

    SSLSocketFactory sslsocketfactory = (SSLSocketFactory) SSLSocketFactory.getDefault();
    SSLSocket sslsocket = (SSLSocket) sslsocketfactory.createSocket(&quot;somehost.dk&quot;, 3049);
    InputStream inputstream = sslsocket.getInputStream();
    // do anything with the inputstream results in:
    // java.net.SocketTimeoutException: Read timed out

I am not even sure that the client certificate is the problem here.


Java client certificates over HTTPS/SSL

I have a requirement of having to run multiple tomcat server in single physical box. While accessing these from a browser, when user switches between the applications, it results in logging out the user previously access application. This is because of JSESSIONID cookie conflict.

One possible solution is to run each applications in different context. Unfortunately, my applications will not work in context path setting as none of the resources are accessed with request.getContextPath() prepended in front. 

This leaves me to change the name of cookie JSESSIONID to resolve the conflict. Is there a way to do this? If yes, how?

Hope I&#39;m clear in stating my question.

Note: All my application are running in different port in the same machine.

Changing cookie JSESSIONID name

Can anyone suggest to me how I can pass a parameter to a thread?

Also, how does it work for anonymous classes?

How can I pass a parameter to a Java Thread?

I just downloaded and installed the new Android SDK. I wanted to create a simple application to test drive it.

The wizard created this code:

    package eu.mauriziopz.gps;

    import android.app.Activity;
    import android.os.Bundle;

    public class ggps extends Activity {
        /** Called when the activity is first created. */
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);
        }
    }

but [Eclipse][1] gives me the error

&gt; R cannot be resolved

on line
    
    setContentView(R.layout.main);

Why?

PS: I do have an XML file named `main.xml` under `res/layout/`.

  [1]: http://en.wikipedia.org/wiki/Eclipse_%28software%29


R cannot be resolved - Android error

I installed the [Maven][1] plugin for [Eclipse][2], and then I got an error like below:

&gt; please make sure the -vm option in eclipse.ini is pointing to a JDK

How do I use the `-vm` option to point to my JDK in eclipse.ini?

  [1]: http://en.wikipedia.org/wiki/Apache_Maven
  [2]: http://en.wikipedia.org/wiki/Eclipse_%28software%29


How do I set the eclipse.ini -vm option?

I&#39;ve downloaded, unzipped and setup Eclipse 3.4.2 with some plugins (noteable, EPIC, Clearcase, QuantumDB, MisterQ). 

Now I find when I&#39;m editing Java projects the code completion is not working.  If I type `String.` and press &lt;kbd&gt;ctrl&lt;/kbd&gt;+&lt;kbd&gt;space&lt;/kbd&gt; a popup shows &quot;No Default Proposals&quot; and the status bar at the bottom shows &quot;No completions available&quot;.

Any ideas?

Eclipse/Java code completion not working

I have Eclipse 3.4.2 installed on Windows with subclipse. Another developer added an SVN repository with his credentials and selected &#39;Save password&#39;. Now every time I do anything with SVN his cached credentials are used. How can I change them to mine?

I have already checked the &#39;workspace/.metadata/.plugins/org.tigris...&#39; folders, and could not find any way to reset those cached credentials.

How to change credentials for SVN repository in Eclipse?

I have an odd problem. In Eclipse Ganymede, I used to be able to highlight a variable, and it would highlight the use of that variables in that method. However through some action I have now disabled it. Is there a way I can enable it? 

I tried searching Google, but since I don&#39;t know what the feature is called, its kinda tough.

Its a really useful feature, and its annoying that its not working.


Content Type	Original Author	Original Content on Stackoverflow
Question	Aaron Fi	View Question on Stackoverflow
Solution 1 - Java	Jon	View Answer on Stackoverflow
Solution 2 - Java	digitalbreed	View Answer on Stackoverflow

In eclipse, while debugging, how do I access the interactive-top-level (a.ka. the "display console")?

Java Problem Overview

Java Solutions

Solution 1 - Java

Solution 2 - Java

How can I have a 64-bit integer in PHP?

Overriding GetHashCode for mutable objects?

Attributions