JDT Tip: See different hovers in Java editor by using modifier keys

•  When you move the mouse over an identifier that has no error or warning, by default a hover with the Javadoc is shown. 

• However if there is an error or a warning on the identifier then the corresponding message is shown.

  

• To see the Javadoc even in this case, you can enable the Javadoc hover on this preference page and define a key modifier e.g. Ctrl+Shift. 

  

• Now press Ctrl+Shift while hovering to see the javadoc.

JDT Tip: Mark Occurrences in Java editor

I think everyone knows that the Java editor highlights occurrences of variables and method calls.

But did you know that it also highlights

• Method exit points - select (or place caret in) the method return type

• Method calls or statements throwing an exception - select (or place caret in) an exception in a catch block

• Break/Continue targets - select (or place caret in) break or continue keywords

Mobile sessions at IBM Innovate

Attending Innovate 2011 ? Interested in mobile development ? If yes, then the following sessions might be of interest to you.

Mon, Jun 6, 2011
4:15 PM : ALM-1602A Bringing Collaborative Lifecycle Development to Mobile Software
8:00 PM : BOF-2303A How is the Need for Developing Mobile Applications Changing Development Efforts

Tue, Jun 7, 2011
1:45 PM : CS-1359B Agile Adoption for Android Mobile Project using IBM Rational Team Concert - Samsung SDS Agile Transition

Wed, Jun 8, 2011
11:15 AM : SE-2206A Mobile Application Development: Strategies for Accelerated Delivery and Deployment
1:45 PM : MAC-1756A Web 2.0 and Mobile Development Fast and Easy with IBM Rational Application Developer 8.0
3:00 PM : PPM-1300A Importance of Understanding User Needs in Mobile Development
3:00 PM : SIS-1609A Model-Driven Development for Mobile Applications

In addition there are also some demo pedestals in the Solution Center. 

Eclipse Day India 2011

Anshu Jain started of the day with an excellent talk Eclipse - A Framework of Frameworks. In his talk he went through the design of a very simple calculator framework to explain all the things that Eclipse does - extensions, dynamic loading, plugin discovery etc. There was also a .cff file (calculator framework format) equivalent to plugin.xml in Eclipse. The example code from his talk is available at his site - highly recommended for someone starting of with plug-in development.

Ankur followed up with another great talk Good Practices for Plug-in Developers.  Some of the images he used to drive his point home were really funny and awesome. I thought my session JDT Bootcamp (JDT Tips and Tricks, and Extending JDT) went well, of course the fact that Satyam did a fantastic job of explaining the Java Model and the Search APIs helped a great deal.

There was a lot of interest in What's new in Java 7 talk by Ayush (the guy with the funny pose in the above pic), which was nice to see. After this Praveen talked about his experience at Adobe with migrating a Eclipse 3.x application to Eclipse 4.x platform. It was nice to hear that Adobe wants to stay on the latest Eclipse platform and has made considerable progress in this regard.

The day ended with an interesting talk about Eclipse UOMo project. Werner Keil gave a few funny examples on what can go wrong if the proper care is not taken in consistently interpreting the units, for e.g. if one team uses inches and feet and the another team interprets the values as meters and centimeters. The image of an upside down NASA shuttle because someone messed up the measurement units will always stay in my mind :)

Lastly a big thank you to SAP Laps for hosting the event! You have been a great host for Eclipse Day India 2011 and the demo camp in Nov 2010. However I would like to see the next Eclipse event in Bangalore hosted at a different venue - just for variety :) Maybe other organizations can step forward. 

I almost forgot, the 'discussion' over drinks in the evening with fellow Eclipse committers and Eclipse users was 'entertaining' ;-) Those who could not join us for drinks, please do next time.

Eclipse JDT and Java 7

Will Eclipse 3.7 include support for Java 7?
Short answer: No
Slightly longer answer: "Due to late availability of JSR-292 (Invoke Dynamic) and JSR-334 (Project Coin) and due to the official release date (July 28, 2011) of Java 7 being after 3.7 ships we had to defer the Java 7 support to 3.7.1. It has not yet been decided whether this will be available as part of the 3.7.1 downloads or as separate feature update.

The work for the Java 7 features is currently in progress in the 'BETA_JAVA7' branch and we will deliver separate updates for the stable builds in order to provide early access to the Java 7 features for interested parties."
See bug 288548.

What is the current status of support for Java 7 in JDT ?
Take a look at the wiki page: http://wiki.eclipse.org/JDT_Core/Java7

I want to try some of the new features of Java 7 in Eclipse
At this point in time you will need to

• Create a new CVS repository location to:
• :pserver:anonymous@dev.eclipse.org:/cvsroot/eclipse
• Check out the following projects from BETA_JAVA7 branch:
• org.eclipse.jdt.core
• org.eclipse.jdt.ui
• Launch another eclipse application from this workspace or export the two plugins into the host eclipse.
• Of course you will also need to install a JDK7 build as an installed JRE.

Debugging Eclipse builders

Do you think Eclipse builds too often ? Do you think Eclipse build too much ? At least I do, or maybe I just got tired of seeing 'Building workspace: (12%)' in the status bar. Anyway I decided to see for myself what the heck the builders were doing.

I use JDT and PDE which means there are two builders of interest

• Java Builder
• API Analysis Builder

There are also Plug-in Manifest Builder and Extension Point Schema Builder, but I think these two do not do much and hence do not take much time.

To know what these two builders are doing in your running Eclipse instance two things are required

• Start Eclipse with -debug option, to me more precise I used the following to redirect the debug output to a file as the debug output can grow large very soon and overflow the console buffer
•  eclipsec –debug > log.txt

• Enable debug options for three plug-ins (details below)
• org.eclipse.core.resources
• org.eclipse.jdt.core
• org.eclipse.pde.api.tools

All three plug-ins ship a .options file containing all the debug options provided by these plug-ins, just open the the corresponding jars in your eclipse installation to get the .options files. Create a single .options file from these and place it in the same directory as eclipsec.exe before starting eclipse.

I had the following options set to true in my .options file
###################################################################
# Turn on debug tracing for org.eclipse.jdt.core plugin
org.eclipse.jdt.core/debug=true

# Reports java  builder activity : nature of build, built state reading, indictment process
org.eclipse.jdt.core/debug/builder=true

# Reports java builder stats
org.eclipse.jdt.core/debug/builder/stats=true

###################################################################
# Debugging options for the org.eclipse.core.resources plugin.

# Turn on debugging for the org.eclipse.core.resources plugin.
org.eclipse.core.resources/debug=true

# Reports the start and end of all builder invocations
org.eclipse.core.resources/build/invoking=true

# Reports the start and end of build delta calculations
org.eclipse.core.resources/build/delta=true

# For incremental builds, displays which builder is being run
# and because of changes in which project.
org.eclipse.core.resources/build/needbuild=true

# Prints a stack trace every time an operation finishes that requires a build
org.eclipse.core.resources/build/needbuildstack=true

###################################################################
# Turn on debug tracing for org.eclipse.pde.api.tools plugin
org.eclipse.pde.api.tools/debug=true

# Reports incremental builder activity : nature of build, indictment process,...
org.eclipse.pde.api.tools/debug/builder=true

# Print notified compatibility deltas
org.eclipse.pde.api.tools/debug/delta=true

# for the tag scanner
org.eclipse.pde.api.tools/debug/tagscanner=true

# for API profile
org.eclipse.pde.api.tools/debug/apiprofile=true

#for api analyzer
org.eclipse.pde.api.tools/debug/apianalyzer=true

#for our workspace delta processor
org.eclipse.pde.api.tools/debug/workspacedeltaprocessor=true
###################################################################

So far I have found a few scenarios where the builders could do less work - Bug 344090, Bug 344110, Bug 344163, Bug 344137. I think there are more issues, but getting a reproducible test case is proving to be a little hard in some cases.

JDT at Eclipse Day India

Satyam and I will be speaking at Eclipse Day India 2011 in Bangalore next week. We have one session JDT Bootcamp. This session consists of two parts. 

JDT - Tips and Tricks (30 min) - In the first 30 mins we will show off useful tips and tricks when working with JDT and Eclipse in general such as tricks in content assist, Java Editor tips, code navigation and debugging aids. 

Extending JDT (60 min) - In the next one hour, we will take you through APIs and extension points that JDT exposes to enable you to extend and customize the Java tooling. Using these APIs, one could create their own cleaunps, refactorings, quick fixes and other utilities.

You may also be interested in Ayush's talk What's new in Java 7 (30 min). This talk intends to describe new features of Java 7 such as switch on strings, binary integral literals and underscores in numeric literals, multi-catch and precise rethrow, diamond, try with resources, etc. The talk will also be interesting to those who want to know the status of Java 7 work in Eclipse compiler.

The three of us will be around the whole day, and would love to answer any questions or get into interesting discussions around JDT :)

See you at Eclipse Day!