jruby ArgumentError: Constructor invocation failed: null

this meant (for me) “you have default-jre-headless installed and are subclassing a JFrame” which doesn’t work right…

so for me it was

sudo apt-get install openjdk-default

to get the non headless one

you can see the real error exception message by not subclassing one but just creating it:

jruby-1.7.16 :001 > require ‘java’
=> false
jruby-1.7.16 :002 > javax.swing.JFrame.new

this should always work…if not then install the non headless package of your jdk.



installing package uuid-devel gives wrong .pc filename /usr/lib64/pkgconfig/ossp-uuid.pc should be uuid.pc

this meant “use the  libuuid-devel package instead of uuid-devel”


packrd@dpsprod-app07.a|dpsprod:~/ltfs-1.2.6$ repoquery -l libuuid-devel

postgres unique substring slow

postgres string index with first characters


anyway the answer is, if you want to query based on a known substring

ok, if you want “like ‘abc%’ then postgres has a special type of index; (I think http://www.postgresql.org/docs/8.1/static/indexes-opclass.html varchar_ops or what not…ymmv).

For us, who had a slow select unique substr then adding an index that was the exact same size works:



how to run os x mavericks/yosemite/mountain lion on old mac/macbook

OK I think I figured it out…maybe.  Haven’t tried it yet.

Anyway if you just want these newer OS’s on your box for testing purposes or what have you, here it is:

install virtualbox

install the newer mac OS as a guest virtualbox in your virtualbox system.

Run it from there.

You may need to adjust the cpu [?]


or google for possibly other answers.

Unclear if this will attach devices like iSight, etc….

unfortunately there seems to be no “pay by hour” virtual mac os x VPS hosts currently <sigh>.

digitalocean console access problem Failed to establish a connection to the console. Please reload.

Failed to establish a connection to the console. Please reload.

Thank you for writing, I’m sorry to read you’re having issues with your Web Console. I can confirm it is currently functioning properly from our end, there are a few scenarios where console access from the control panel may be difficult or impossible:

1. If you are behind a restrictive firewall. Opening ports 6000-7000 will usually clear this up.
2. If you are on a network with a double-NAT configuration.
3. If you are behind a web-proxy (almost all mobile broadband connections configure a proxy).
4. If you are on a satellite or other high latency connection as this can cause timeouts.

Some additional steps you can take to troubleshoot the issue further are:

1. Clearing your browser’s cache
2. See if you are able to replicate the issue in another browser
My answer: make sure your proxy is set in windows’ LAN connections settings, then it will work past draconian proxies