Nice job of expaining how to set up a self-signed cert in IIS 7.
Self-Signed certs in IIS 7
Saturday, July 17, 2010
Sunday, July 11, 2010
Maven Mysteries - Generics and Compiler Issues
Maven by default compiles code with a lower compiler version than 1.5 which has support for generics.
Today I was programming along when suddenly a project that has been compiling for a while suddenly stopped compiling (using Maven + Eclipse) and Maven started griping about the project code's inclusion of generics when this is not supported prior to JDK 1.5. Hmm. I had this working before so why did it suddenly start failing? Who knows.
So I go in and reset the project to use the 1.6 compiler by right clicking on the project node in Eclipse, choosing compiler and changing the settings.
No dice.
I then right clicked on the project node, chose Maven (I'm using Maven plugin as described in another post) and choose "Update Project Configuration". Right click on the pom, choose Run As and Maven Install...well then I started getting compiler errors in Eclipse I wasn't getting before. I went to one of the errors, right clicked and told it to change the project to use JDK 1.5 which supports generics.
Ok now it compiles...but now the setting changes I just made say 1.5 instead of 1.6. Why didn't it work when I set the project to use JDK 1.6? So I go back to the project node, change the compiler setting to JDK 1.6. Still compiles. That's good.
Then I go right click and choose Maven and Update Project Configuration. Running Maven Install still works.
OK great. Whatever.
Today I was programming along when suddenly a project that has been compiling for a while suddenly stopped compiling (using Maven + Eclipse) and Maven started griping about the project code's inclusion of generics when this is not supported prior to JDK 1.5. Hmm. I had this working before so why did it suddenly start failing? Who knows.
So I go in and reset the project to use the 1.6 compiler by right clicking on the project node in Eclipse, choosing compiler and changing the settings.
No dice.
I then right clicked on the project node, chose Maven (I'm using Maven plugin as described in another post) and choose "Update Project Configuration". Right click on the pom, choose Run As and Maven Install...well then I started getting compiler errors in Eclipse I wasn't getting before. I went to one of the errors, right clicked and told it to change the project to use JDK 1.5 which supports generics.
Ok now it compiles...but now the setting changes I just made say 1.5 instead of 1.6. Why didn't it work when I set the project to use JDK 1.6? So I go back to the project node, change the compiler setting to JDK 1.6. Still compiles. That's good.
Then I go right click and choose Maven and Update Project Configuration. Running Maven Install still works.
OK great. Whatever.
Classloaders In Depth
Digging into the details of classloads has been on my list of research items for a while. I understand the concepts and the implications - what if a class gets loaded other than the one you intend to be running in your app and you're not really running the code you think you are?
Anyway...ran into this error today...
java.lang.LinkageError: loader constraint violation: when resolving method "[class]" the class loader (instance of [classloader1]) of the current class, [class], and the class loader (instance of [classloader2]) for resolved class, [class], have different Class objects for the type [class in conflict] used in the signature
Which led me to this great blog post which does a great job of epxlaining the nitty gritty of class loaders and potential issues with self-first and parent-first class loading...
Java Class Loaders
Nice.
Oh and by the way, I fixed this by changing the package of the class in my web app so it was different than the package of the conflicting class loaded by the web server. This may not be the right solution in all cases - you may want to remove the class from your web app and use the parent class or vice versa instead.
Anyway...ran into this error today...
java.lang.LinkageError: loader constraint violation: when resolving method "[class]" the class loader (instance of [classloader1]) of the current class, [class], and the class loader (instance of [classloader2]) for resolved class, [class], have different Class objects for the type [class in conflict] used in the signature
Which led me to this great blog post which does a great job of epxlaining the nitty gritty of class loaders and potential issues with self-first and parent-first class loading...
Java Class Loaders
Nice.
Oh and by the way, I fixed this by changing the package of the class in my web app so it was different than the package of the conflicting class loaded by the web server. This may not be the right solution in all cases - you may want to remove the class from your web app and use the parent class or vice versa instead.
Saturday, July 10, 2010
Strange Network / Web Site behavior
Something very odd happened when I transferred web sites from one network to another, and view them using one particular network provider.
If I hit the web sites in rapid succession the images go all wacky and some images will get displayed multiple times when they are only supposed to be displayed once, for instance. These are straight html pages - about as basic as you can get.
I cannot reproduce this skewing of the web pages when working locally on the machine that is hosting the web site.
I also noticed that when I strolled down to the local coffee shop with my laptop I could not reproduce this funky behavior. This leads me to believe that the problem is due to the network or software thereon of the ISP at the particular location having the problem. It seems like something is capturing and altering the results of the request in transit and at some point before reaching my computer they are getting skewed.
Will have to research further.
7/15/2010
Interesting...last night I uncovered that my mail seemed to be going through a proxy server. They claimed that my network traffic was not going out through any proxy servers previously, but I asked them to double check the web traffic since obviously something was affecting the email traffic and sending it where it shouldn't be going.
Magically today, I have not yet been able to reproduce whatever was causing web sites to be skewed. I have not yet tested on Comcast network again.
If I hit the web sites in rapid succession the images go all wacky and some images will get displayed multiple times when they are only supposed to be displayed once, for instance. These are straight html pages - about as basic as you can get.
I cannot reproduce this skewing of the web pages when working locally on the machine that is hosting the web site.
I also noticed that when I strolled down to the local coffee shop with my laptop I could not reproduce this funky behavior. This leads me to believe that the problem is due to the network or software thereon of the ISP at the particular location having the problem. It seems like something is capturing and altering the results of the request in transit and at some point before reaching my computer they are getting skewed.
Will have to research further.
7/15/2010
Interesting...last night I uncovered that my mail seemed to be going through a proxy server. They claimed that my network traffic was not going out through any proxy servers previously, but I asked them to double check the web traffic since obviously something was affecting the email traffic and sending it where it shouldn't be going.
Magically today, I have not yet been able to reproduce whatever was causing web sites to be skewed. I have not yet tested on Comcast network again.
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