Unable to connect to the Java VisualVM Plugins Center because of Server returned HTTP response code: 503 for URL: http://www.oracle.com/splash/java.net/maintenance/index.html
There is a solution.
TLDR: the quick answer is to change the URL used by the tool (Tools>Plugins>Settings) to use a new URL, such as https://visualvm.github.io/uc/8u131/updates.xml.gz.
For those who'd appreciate more detail, read on.
Note: This blog post is from 2014. Some content may be outdated--though not necessarily. Same with links and subsequent comments from myself or others. Corrections are welcome, in the comments. And I may revise the content as necessary.I'd like to recommend four free tools that I think everyone (running Windows) should consider installing on their machines, as they can help with day to day tasks that many (certainly I) hit every day.
They don't run in the background, only doing their job when you ask them to, so I find them safe to install and use on production servers, though of course any tool can be abused. I've never seen these to cause a problem in many thousands of uses.
I was reminded to share this list today as I was helping a customer, as I got on their server with them to help them solve a problem. I recommended we install these as I do on nearly all my engagements (and indeed on all my own machines). I think they really are fundamental tools, as I'll explain below.
Note: This blog post is from 2013. Some content may be outdated--though not necessarily. Same with links and subsequent comments from myself or others. Corrections are welcome, in the comments. And I may revise the content as necessary.Someone asked on the FusionReactor mailing list (a Google Group) whether FusionReactor tracked CF sessions. I started to write a reply, with the good news/bad news in answer to that, and as sometimes happens, it became long enough that I thought it might be better suited as a blog entry that I could point to from the list instead, and which may also help those not on the list (which is a great resource, as a low-volume list with a high signal to noise ratio.)
Anyway, here is the answer I wanted to offer to that question...
Note: This blog post is from 2012. Some content may be outdated--though not necessarily. Same with links and subsequent comments from myself or others. Corrections are welcome, in the comments. And I may revise the content as necessary.I often see people struggling with confusion over what hotfixes have been applied to CF. They may wonder "which have we applied?", or worse, they may not have applied any and just don't know "how to know" whether they have. I have good news, but it may not be the answer most would suspect.
The common answer offered is that one should use the "system info" page in the CF Admin, and its available "update level" field.
But I will assert that's not the "right answer" after all, or certainly not the "best answer" to really know what hotfixes (plural) have been applied. Know why? If not, I'll explain here, and I'll show what I would say is the "right" answer to "what hotfixes have you applied?"
Need to solve browser problems? Did you know most modern browsers now have built-in developer tools?
For years, experienced developers have recommended client-side proxy tools like Firebug, Fiddler, Charles, and such. I list these and many others as a category in my CF411 site listing over 1800 tools and resources for CFers, in the category, HTTP Debugging Proxies/Sniffers/Web Client Test Tool.
I recently updated the list, though, to point out these "built-in" forms of these tools, now available in most browsers. If you may be in a place where you are "not allowed" to install new software (or are simply disinclined), knowing that the browser may have such a valuable tool built-in can be a real discovery, thus this entry.
Here's the content that I've added to that section:
- In Chrome, see the Dev Tools, available under the "Customize and control Google Chrome" icon at the top right (the monkey wrench), then Tools>Developer Tools.
- In Firefox 6 and above, see the "Web Console" feature in the "Web Developer" tools, available under the Tools menu.
- In Internet Explorer, see the Developer Toolbar which is an ad-on for IE 6 and 7, and the f12 Developer Tools that are built into IE 8 and 9 (in the Tools menu).
- In Opera, see the Developer Tools in Opera DragonFly, available in the Edit>Developer Tools menu in Windows, and Tools>Advanced on Mac.
- In Safari, see the "Web Inspector" feature of the Develop menu.
- I welcome additions/corrections/feedback.
The links I've given for each of these often have friendly introductions to using such tools. I can also commend an old but classic discussion of such tools, here.
Have you used these sort of tools? How have they helped you. Are you surprised to learn that the browsers now have such tools built-in? Chime in and share your thoughts. I may do a later blog entry or talk introducing using these tools for some common problems working with CF.
Note: This blog post is from 2010. Some content may be outdated--though not necessarily. Same with links and subsequent comments from myself or others. Corrections are welcome, in the comments. And I may revise the content as necessary.If you have any reason to look at large files (especially log files) on Windows, don't use NotePad (it doesn't like large files)! Sure, you can perhaps use WordPad, or you may be using a favored editor like TextPad, UltraEdit, NotePad++, and so on. But those are editors: they generally presume you want to change the file.
If you just want to look at a file, there's a great free tool to do it: UniversalViewer.
It can open a 1GB file as fast as a 1kb file (because it only pulls in what it needs to show the screen full of text you're looking at.) And there are times when you may well need to look at some very large files, especially when troubleshooting CF servers, like I do.
And actually, as its name implies, UniversalViwer can view far more than just text files, including images and more.
I've just only ever used it for looking at log files, for which it excels (and yes, you can search within the file, set it to tail files, and more.)
I've been touting the tool for years in classes and presentations, and I was about to mention it in another blog entry, but then I realized I'd not blogged about it on its own. Rather than have the reference lost in another blog entry, here's its moment to shine!
And yes, I do realize there are several other tools that can do this. I list this one and several others in a category of my CF411 list: Generic File View/Log Analysis Tools. (Note that there are some nifty tools in that category there for looking specifically at CSV files, as well as other entire categories for specific kinds of logs, like CF logs, web server logs, windows event logs, etc.)
Note: This blog post is from 2010. Some content may be outdated--though not necessarily. Same with links and subsequent comments from myself or others. Corrections are welcome, in the comments. And I may revise the content as necessary.Are you still suffering from spam or junk mail in your email inbox? If you're using Outlook or Thunderbird, you should consider CloudMark, a service I've used for years. I'd like to share a bit about it, for those who may benefit.
Before proceeding though, let me say that I realize there are many spam solutions, including ones based on your mail server instead (that you or your host might implement).
And yes, of course I do realize that folks using Gmail will want to say that they never have to worry about this at all!
Let me please just speak to those who do choose to (or have to) receive email from other mail servers, and perhaps can't control spam handling on the server, or still favor a client solution.
Note: This blog post is from 2010. Some content may be outdated--though not necessarily. Same with links and subsequent comments from myself or others. Corrections are welcome, in the comments. And I may revise the content as necessary.Some time ago I implemented some code on my own site to throttle when any single IP address (bot, spider, hacker, user) made too many requests at once. I've mentioned it occasionally and people have often asked me to share it, which I've happily done by email. Today with another request I decided to post it and of course seek any feedback.
It's a first cut. While there are couple of concerns that will come to mind for some readers, and I try to address those at the end, it does work for me and has helped improve my server's stability and reliability, and it's been used by many others.
Update in 2020: I have changed the 503 status code below to 429, as that has become the norm for such throttles. I had acknowledged it as an option originally. I just want to change it now, in case someone just grabs the code and doesn't read it all or the comments.
Background: do you need to care about throttling? Perhaps more than you realize
It also gives me a chance to offer some props for the site of the company behind the tools, SolarWinds, which again many may find valuable in educating not only about the tools but the topics that the tools help with.
The free SAN and VM monitoring toolsThe two tools (and one more for bonus) are:
- SolarWinds Free SAN Monitor - keep a close eye on the performance & capacity of your storage arrays and become a storage superhero!
- VM Monitor - continuously monitor a VMware® ESX Server and its virtual machines with at-a-glance virtualization health statistic
- WMI Monitor - monitor your Windows® apps and servers in real time, using built-in, community-sourced, and customizable application templates!
I haven't yet used them myself, so this isn't so much a recommendation of the tools but rather a recommendation that you consider them if you are interested in what they have to offer.
The company offers still more free tools, as well commercial ones of course.
A company that gets how to educate you about their products
You may have noticed above that I offered as well links to videos about each product. SolarWinds has really done a great job offering educational resources, especially videos, and organizing them into categories such as tech talks, webcasts, and more.
Indeed, if you may be new to network management (which can be a broad and/or deep subject, appealing variously to generalist IT geeks and hard-core network admins), they offer lots of compelling introductory resources, including their geek guides and even certification training . Of course they also have a helpful blog and twitter feed.
Just as I previously praised the Mura folks as a "company who got it right" in terms of setting up a compelling, informative web site for IT folks, I really have to say the same for the SolarWinds folks. Congrats, and thanks.