Develop Reference

Not able to start zookeeper thus apache kafka

I downloaded Kafka on my local pc windows for development and it comes with zookeeper in it. When I try to start zookeeper using the below command, I'm getting the below error.
zookeeper-server-start.bat config/zookeeper.properties
and it gives me error message
error missing 'server' jvm at 'C:\Program Files
<x86>\Java\jre1.8.0_65\bin\server\jvm.dll' please install or use the
JRE or JDK that contains those missing components.
Can anyone please suggest a solution for this?

RE: the question, seems Java is not installed properly. I generally use Ninite website to get Java as it'll ensure you get the latest version (which you'll want 64-bit Java anyway)
im running zookeeper-server-start.bat config/zookeeper.properties from bin/windows folder in kafka folder
If you are currently in the bin/windows folder, run dir... Do you see a config folder there? That is what the error is telling you; that that folder & config file do not exist.
You can either reference ..\config\zookeeper.properties, or move up a folder to where you extracted Kafka (let's say C:\kafka for example), and you should be able to run like so
C:\kafka> bin\windows\zookeeper-server-start.bat config\zookeeper.properties
As #Deadpool mentions, though, it might help if you setup a KAFKA_HOME variable, then you can do this from any location
%KAFKA_HOME%\bin\windows\zookeeper-server-start.bat %KAFKA_HOME%\config\zookeeper.properties

Eclipse with EclipseLink: How?

I am using ubuntu. I want to build a JPA project with eclipse. According to that tutorial I need to have EclipseLink.
Therefore I went to EclipseLink download page, got .zip achive and tried to follow instuctions - set the paths.
JAVA_HOME - Set JAVA_HOME to where you installed your Java SDK home >directory
UNIX example: JAVA_HOME = ...:/usr/java/jdk
PATH - Set PATH to include JDK/bin directory.
UNIX example: PATH = ...:/usr/java/jdk/bin
okay. My SDK Eclipse, and it is located in /usr/lib/eclipse. Though I also have /usr/lib/java/swt-gtk-3.8.jar. What should I use here?
Next. Then I take unziped eclipselink folder. It is written, that I should make path to it:
UNIX example: ECLIPSELINK_HOME = ...:/usr/el/INSTALL_DIR/eclipselink
So, for example, I place it like this:
ECLIPSELINK_HOME=/home/laura/lib/eclipselink
Please, help me. Are my steps correct? What I need to do after set all paths?

So, here you are. The answer qas quite simple: I should have had installed the newest version of Eclipse, where I would have an option to make a JPA project. Then goes an option to choose a platform, EclipseLink, for example.

Eclipse RCP: application specific folder

I have an RCP application in Eclipse 4.x for a cross-platform software. I would like to place the osgi.instance.area in the application specific folder. For example on Windows it generally is C:\Users[Username]\AppData[Name]. Something similar to the directories outlined here - http://www.chromium.org/user-experience/user-data-directory.
I have seen the solution here - https://bugs.eclipse.org/bugs/show_bug.cgi?id=241192 but I haven't understood it really well. I use the product editor on Eclipse and under the Configuration tab, I have added the osgi.instance.area property in the Properties section with another directory at the moment.
Then I tried the solution from the bug - $APPDATA$/COMPANY/PROGRAM/instance but I couldn't find the directory anywhere at the expected location. Also, how does this work for Linux and Mac OS X?

In Windows 7 and 8 $APPDATA$ is C:\Users[Username]\AppData\Roaming. In Linux $APPDATA$ is undefined. You should use #none, #noDefault, #user.home, #user.dir, filepath or url

I think it is the osgi.instance.area.default property that you should set. The value migght be something like #user.home/Documents/workspace

Getting JavaFX to run via Browser for Simple HelloWorld app

I tried following various tutorials for getting a JavaFX hello world app running in a browser. I can't believe it's that hard, so I'm looking for any insight into what I may have done wrong. Some things I've tried and resolved (to rule out the obvious):
Had to download 32-bit JRE for the browsers and ensure they were using that
Thus using the latest JRE (7u21); running on Win 7 64-bit
Checked Windows Control Panel -> Programs -> Java to verify the JRE being used
Signed the JAR file
Tried running from local file, found that drive letters weren't recognized, so moved to running via Tomcat 6
Tried various changes to the codebase and url hrefs, but I believe those are correct.
Tried in both IE 10 and Chrome
What I ended up with was that loading the .html (which references the jnlp using the JavaFX default javascript) would spin for a while then fail. If I try to load the .jnlp file directly, I get an exception:
ClassNotFoundException: javafx.application.Application
I verified that the jfxrt.jar is in the lib folder of the JRE that the browser is using.
Any insight/suggestions as to what I may be missing at this point? Seems like it must be something obvious/basic at this point, but I'm not seeing it. Thanks.

Just to follow-up, I went ahead and used javafxpackager. That produced a web page that would load the JavaFX application in Chrome. However, it still doesn't work in IE. I'm going to write that off as an IE but since it works in Chrome. What I did learn by looking at the results, though, is there are several things javafxpackager does, and the results of that are not exactly what's described in most of the manual tutorials/examples. Minor differences, but apparently they matter.

It sounds as you don't have the JavaFX starter classes in your JAR (usually done by the Ant script) and don't have the correct JavaFX Manifest entries.
It should not be needed to add the jfxrt.jar as a resource to your JNLP file and you shouldn't have to sign it.
Please show your Manifest file.
The Manifest file should contain at least the following JavaFX entries:
JavaFX-Version: 2.2
JavaFX-Application-Class: yourPackage.YourApplication
Main-Class: com/javafx/main/Main
The JAR should contain the classes of the com.javafx.main package provided by the ant-javafx.jar (see /resources/classes in that Jar). The ant-javafx.jar is provided by the JDK.

I was able to mostly resolve my problem. I'm using Eclipse, not NetBeans, so doing a lot manually. The basic problem was that I had to include the jfxrt.jar as a resource in the jnlp file (and that jar also had to be signed).
My app now runs if I access the jnlp directly, though it still doesn't work via html page. I'll post an update if/when I figure that part out.

What is the recommended/standard install path for apache-tomcat on a linux box

Hello I am looking to install Apache-Tomcat on a RedHat linux and I am interested if there is a standard place for this to be installed. in other work I have seen tomcat installed at
/opt/apache-tomcat-[VERSION]/
but I would expect it to be found under /usr.
Best answer will have a link to authoritative site.
Thanks so much,
David.

I don't know if there's such a thing as an "official" place, but a reasonable thing to do would be to do what you've done and refer to tomcat through a softlink at /usr/local/tomcat or some such, which would allow you to upgrade versions by simply installing a new version in opt and changing the softlink.

It depends on who you ask, but I see it this way:
/opt is typically for third-party add-on software. /usr/ is often for 'system' software. User compiled apps go in /usr/local.
I put tomcat in /opt/apache-tomcat-VERSION. I then make a symlink to it as /opt/tomcat.
The Linux Standards Base may have more info on the matter.

There's a Red Hat RPM package for Tomcat 6 - just "yum install tomcat6" and it will put everything in the right place for you and fix up the security by running Tomcat as a dedicated user (not to mention taking care of updates and patches by putting Tomcat into the RPM repository).
Most of the executables, the configuration and the webapp directory end up under /var/lib/tomcat6 using this method.

Someone else mentioned http://www.pathname.com/fhs/pub/fhs-2.3.html, which is good information. Unfortunately, they didn't provide any accompanying information with it, aside from a snarky comment.
According to that document, /opt is where installed software would go, so I would recommend /opt/tomcat, and set CATALINA_HOME to this directory.
It also says /var is where variable data would go, so I would put it in /var/tomcat and set CATALINA_BASE to this directory.
I'll add a little background. If you don't set CATALINA_BASE, then it will default to the same as CATALINA_HOME. However, CATALINA_HOME should be the unadulterated install, and should be set as read-only. You should use a different location for variable stuff like your actual web directories and logs. Then, when you need to change versions, it's just as simple as changing CATALINA_HOME. Also, you can run multiple instances of Tomcat more easily without having multiple copies of the same install.
Also, don't forget to create a CATALINA_BASE/bin/setenv.sh (or .bat for Windows) file instead of editing CATALINA_HOME/bin/catalina.sh (or .bat for Windows).
Yeah, this is more information than anyone asked for, but hopefully someone will find it useful.

Well there is an easy answer for that here, too bad nobody of these high-pointers have listed it:
http://www.pathname.com/fhs/pub/fhs-2.3.html

I'm fairly certain it doesn't matter.
Just like most well-behaved Java apps look for the JAVA_HOME environment variable to locate the preferred Java installation, once you've set CATALINA_HOME in either .bashrc or .profile of the affected users, software needing to locate Tomcat should be able to find it.