8. January, 2015
In this article, I’m trying to collect the steps to find out the reason when Eclipse is suddenly slow:
- Java GC. To find out if that’s the culprit, go to Window -> Preferences -> General and enable “Show heap status”. You will get a little gauge at the bottom of the Window. If the gauge is almost full, then you probably have too little memory.
a) Give Eclipse more memory
b) Close some projects
c) Deinstall or disable unnecessary plugins
- Check the Eclipse Error Log. Maybe there is a problem under the hood.
- Some plugin is acting up. Enable Eclipse’s own logging (see below) and watch the console.
Some plugins have their own console (Groovy, Maven). In the Console View, click the arrow of the “Open Console” button to get a list. The Stacktrace Console – a useful tool to examine stacktraces from some external source – is also hidden there.
- The metadata got corrupted. Clean it.
Enable Eclipse’s Console Logging
When you start a Java application inside of Eclipse, you can see the output in a console view. You can do the same for Eclipse itself.
Open eclipse.ini and add these lines right before -vm (or -vmargs, if there is no -vm line):
See “Debug Mode“, “Eclipse runtime options” and “FAQ How do I use the platform debug tracing facility”
On Windows, make sure Eclipse is started with java.exe instead of javaw.exe.
Eclipse will log errors and trace information to the console window. Check the output.
Many Eclipse plugins offer a range of trace options. You can see them if you open the plugin JARs. Look for a file called “.options”.
If you copy some of those into a file “.options” in the same folder as “eclipse.ini”, you can able various logging options.
Here is an example what the file could look like:
Maven m2e Plugin
If the m2e plugin causes problems:
- Look into the Maven console.
- Try Maven from the command line to see whether it’s a problem with the project in general or with m2e.
- Tweak the logging options of m2e by editing
28. December, 2014
There is this old joke on User Friendly about license agreements: “Have any of you ever actually read a license agreement?” “I have! A few words, anyway …” “And what did the part you read say?” “umm… ‘I accept.'” (whole story starts here; afterwards, someone actually wrote a version of Clippy for Vim called Vigor).
I remembered all this when I saw this video on YouTube:
And that led me to an idea: How about an app which tracks T&C for you? In general, it should take a license and show you the important bits. Then, you could say “okay, I like that and that and I can live with those.” The app would then remember your preferences. For the rest of the terms, you could chose “I grudgingly accept these” or “no business with me because of this term.”
Even better, the app could notify you of terms which don’t apply to you because of local law or because courts ruled them out.
That way, the app could just show you the parts of a new license which you want to know about, that is the parts which you didn’t already agree to and without the parts that you’d accept anyway.
23. December, 2014
Eine kleine Hilfe für alle Leser der c’t, welche einfach(er) einige Artikel archivieren wollen: Das verlinkte Script unten sortiert das Inhaltsverzeichnis im Archiv nach Seitenzahl wenn man auf “aktuell” klickt.
8. December, 2014
If you see this error while running the code from Eclipse, check the .classpath file for this line:
<classpathentry exported="true" kind="con" path="GROOVY_SUPPORT"/>
In this case, Eclipse adds version 2.1.8 to the classpath and Maven adds 2.1.9. At runtime, Groovy detects both versions and aborts since this will cause subtle bugs.
Solution: Delete the line above in the .classpath file.
If you see a line which contains GROOVY_DSL_SUPPORT, then you can leave that in – the Groovy plugin will use the JARs which Maven adds to the classpath.
3. November, 2014
RCP Testing Tool (RCPTT) is an Open Source tool for UI testing of Eclipse-based applications. During the demo by Ivan Inozemtsev, I got the impression that they thought of everything:
- There is a recorder so you can quickly create a test case by clicking thought the application
- There is an assertion builder where you can say “this element should be red”, “this checkbox needs to be checked”, “this image must be visible”
- There is special support for all kinds of widgets like text editors where “position” is row/column (i.e. cursor position) instead of mouse coordinates or character offsets. The test API allows for checks like “is styled like a keyword”.
- If the UI is resized after the tests have been recorded, the tool will try to calculate the relative click point. Unless the UI element is special (like a graph editor) where it has different heuristics (like when you clicked in an empty area but now, there is something below at the coordinate). If everything else fails, the testing tool will try to resize the UI element to the recorded size.
- There is a compact, extensible DSL to describe the test cases. The DSL supports procedures so you can reuse test code.
The tool was fast and stable during the demo. It could reset Eclipse’s workspace to a certain state (open perspective, open editors, open projects) – I’m currently thinking about using it to create the default workspace for our development team.
One more things from the demo: Black box testing is a myth or at least a dream. A testing tool for anything complex needs to know internal details (like Eclipse’s background jobs). Otherwise the tests will either fail randomly when some background job didn’t complete in time or they will be slow (since each of them will be sprinkled with “WAIT 1 MINUTE” instructions) or they will be sprinkled with application specific “wait” instructions.
3. November, 2014
The last two talks were about testing.
“Automating user interface tests with behavior-driven development (BDD)” by Jose Badeau and Dietmar Stoll used an Xtext-based DSL to connect requirements, wireframes and test descriptions so they can validate each other. In the example, they removed a field from the wireframe mockup and the Eclipse editor for the test cases showed errors where they were used in the DSL.
The demo showed once again how much power lies in connecting information from different sources. If you remember, then this was the key feature which set Eclipse apart from all the other Java tools in 2001: It could bring you to the place where something was defined by pressing F3 or Ctrl+Click. If you changed one file, it would instantly compile all the other files and show you any problems it would find. Having a tool which actively searches for problems saved and still saves a lot of time.
3. November, 2014
In his talk “Modernisation of Software“, Georg Pietrek of itemis AG shows the key points when you need to modernize software (= make large, disruptive changes). Karsten Thoms then demonstrated those points in a practical example in his talk “Model based migration of Oracle Forms applications”.
- Analyze the old code
- Create DSLs that describe the pieces of the old code which you want to migrate
- Write a small demo what the new app should look like
- Develop code generators which take the DSLs to generate the demo
After you have proven that you have covered all important bases this way, you can expand the DSLs (or rather write more code using the DSLs) to migrate the rest of the old code. You can reuse the small demo from step #3 to test any changes to the DSLs and code generators on a small code base.
The big advantage of using models to modernize is that manual migration often runs into a death spiral: Developers start with little knowledge (especially, when the original developers aren’t around anymore). They learn as they migrate code. But as this process advances, it becomes more and more expensive to fix early mistakes. With the model driven approach, you fix the bug in the code generator and thousands of lines of code are corrected at the push of a button. This means you can make abstraction work in your favor.
The advantage over exiting tools to migrate an old code base is that the model based approach is more flexible.
A quote from the talk: “Software doesn’t rot but it’s environment changes.” Eventually, the software no longer meets the needs.