Group items tagged

for each workspace, in files stored in <workspace>/.metadata/.plugin/org.eclipse.core.runtime/.settings

for each project --for project-level settings -- in files stored in a .settings sub-directory of your project folder

Is there an UML editor for Eclipse? An Eclipse Modelling project-based UML editor can be installed from the Eclipse update site "Modelling > UML2 Tools SDK". See Creating UML 2 diagrams with Eclipse UML2 Tools - Tutorial for an introduction.

How do I debug Eclipse? How can I see what plug-ins are being started? Why aren't the plug-ins I installed showing up in the UI? How do I start the OSGi console?

Debugging OSGi Bundle Loading Issues There are a few flags you can pass to Eclipse on the commandline or in your eclipse.ini file that might help: -consolelog - log everything in workspace/.metadata/.log to the console where you launched Eclipse as well -debug - more verbose console output -console - start the Equinox OSGi console to interact with OSGi directly -noexit - when Eclipse closes, keep the OSGi console running until you type 'exit' or hit CTRL-C so you can keep debugging See Where Is My Bundle? for an overview of how to use the OSGi console for diagnosing problems.

Debugging Eclipse Using Eclipse You can also debug an Eclipse instance from another instance through remote debugging: Start the instance to be debugged with "-vmargs -Xdebug -agentlib:jdwp=transport=dt_socket,server=y,address=8000". You should see a message like "Listening for transport dt_socket at address: 8000" Open Run → Debug Configurations... and create a Remote Java Application configuration with connection type "Socket Attach" and connecting to the client at port 8000. Set the project to a bundle project with the right dependencies for the bundles that you are trying to debug. Launch the configuration. The JDWP agent supports other useful arguments, like "suspend=n" so that the process does not suspend. For more details, see Oracle's Java Debug Wire Protocol (JDWP) connection docs.

I just installed Eclipse on my 64-bit system, but it does not start. What is the problem? Make sure that you have downloaded the 64-bit version of Eclipse (it should have x86_64 somewhere in its name) and have installed a 64-bit JVM. Likewise, if you run a 32-bit JVM, then you should use the 32-bit version of Eclipse.

When I start Eclipse it says "Workspace in use or cannot be created, choose a different one.", what should I do? There are a couple of things you can try. Delete the workspace/.metadata/.lock file. Check your running processes to make sure there aren't any remaining Java or Eclipse processes running. When in doubt, restart your computer. :) Try starting Eclipse on a different workspace (from the workspace selection dialog, or by using a command line argument like -data /home/user/tmp-workspace), then switch back to your original workspace.

How do I uninstall a plug-in? You can view your list of installed software by checking your installation details from about dialog. Help > About > Installation Details

I'm having memory, heap, or permgen problems, what can I do? FAQ How do I increase the heap size available to Eclipse? FAQ How do I increase the permgen size available to Eclipse?

Eclipse seems to be hanging on startup. How can I find out why? If none of the solutions outlined in this section reveal the problem, then you can try debugging an Eclipse instance as a debug target from another Eclipse instance. This is surprisingly easy: Start Eclipse in a "new" blank workspace (e.g., C:\TEMP\WS, or /tmp) Create a new Debug configuration: Run -> Debug Configurations; then click on "Eclipse Applications" and select the New Launch Configuration. If you believe it's something about a particular workspace, then set the workspace to your normal workspace. If you believe the hang is caused by a particular plugin, disable the plugin and verify. Launch and then see. Using this approach, you can break with the debugger to see where hangs are occurring. You can also change the selection of plugins that the instance is launched with.

I was working on a project and doing something or other does not work. Where should I start? Try refreshing your projects. Try cleaning your your projects using the menu item Project/Clean to trigger a rebuild. Try closing/reopening your projects. Try restarting Eclipse.

4.2 Where are Eclipse's log files located?

Where are Eclipse's log files located? <workspace>/.metadata/.log You can view this workspace log as a view if you have PDE installed on your computer (which you would if you have downloaded the Eclipse SDK). You can open that view via Window -> Show View -> Other -> PDE Runtime -> Error Log. <eclipse install>/configuration/<sometimestamp>.log <eclipse install>/configuration/org.eclipse.update/install.log

Where are Eclipse preferences stored?

Where are Eclipse preferences stored?

Where are Eclipse preferences stored?

Where are update site bookmarks stored? It is within an XML file called <user_home>/.eclipse/org.eclipse.platform_3.1.2/configuration/org.eclipse.update/bookmarks.xml. Your Eclipse version may vary.

A developer who lacks the ability to give good names to concepts and data in their code is like a mute translator

William Drai

Honestly I don't see any value in switching to CDI if it is

please not this Dao/Template mess

Gavin King

to reproduce the same awful patterns

please not this Dao/Template mess

Because, of course, there are no other well-known patterns for dealing with boiler-plate cleanup code and connection leaks.

This is exactly the kind of

It gives people a

and somehow shuts down their brains so they

It's a very impressive magic trick, and I wish I knew how to do it myself. But then, I'm just not like that. I'm always trying to poke holes in things - whether they were Invented Here or Not.

but that might be too high-level for your taste. Their are other, less-abstract options.

exception handling, this is one area where Spring does a good job: "The Spring Framework's handling of SQLException is one of its most useful features in terms of enabling easier JDBC development and maintenance. The Spring Framework provides JDBC support that abstracts SQLException and provides a DAO-friendly, unchecked exception hierarchy."

Automatic connection closing (and other boiler-plate code) is obviously a hard requirement to be handled by the fwk.

Gavin King

there are a bunch of people

They don't understand, or see the value of, using managed objects to represent their persistent data.

Um. Why? Why would that be a bad thing? I imagine that any app with 1000 queries has tens of thousands of classes already. What's the problem? Why is defining a class worse than writing a method?

very voluminous output

encourages the ProductService approach

it’s not for small projects

this practice was deprecated due to incompatibility problems when the experimental types were standardized

Limitations

may incorrectly classify a content's media type:

FIELD

PROPERTY

Either all annotations must be on the fields, or all annotations on the get methods, but not both (unless the @AccessType annotation is used)

if placed on a get method, then the class is using PROPERTY access

For FIELD access the class field value will be accessed directly to store and load the value from the database

field can be private or any other access type

For PROPERTY access the class get and set methods will be used to store and load the value from the database

PROPERTY has the advantage of allowing the application to perform conversion of the database value when storing it in the object

be careful to not put any side-affects in the get/set methods that could interfere with persistence

Common Problems

Odd behavior

One common issue that can cause odd behavior is

For this reason it is generally recommended to

causing duplicate inserts, missed updates, or a corrupt object model

if you are going to use property access, ensure your property methods are free of side effects

Some people are talkative and tend to wander off into Story Telling

Some people want to engage in Problem Solving immediately

Other topics of discussion (e.g., design discussions, gossip, etc.) should be deferred until after the meeting.

questions should be reversed in order to emphasise the correct order of importance:

Any impediments in your way? What are you working on today? What have you finished since yesterday?

A long, droning meeting is a

to start the day

IDE plugin usage

Suppressing warnings

Rule Sets

All entities marked as [Managed] are considered as corresponding to Hibernate/JPA managed entities on the server

It is highly recommended to use JPA optimistic locking in a multi-tier environment (@Version annotation

In conclusion, the recommended approach to avoid any kind of subtle problems is to have a real uid property which will be persisted in the database

Here all loaded collections of the Person object will be uninitialized so uperson contains only the minimum of data to correctly merge your changes in the server persistence context

Tide uses the client data tracking (the same used for dirty checking, see below) to determine which parts of the graph need to be sent.

Dirty Checking and Conflict Handling

Data Validation

Tide integrates with Hibernate Validator 3.x and the Bean Validation API (JSR 303) implementations, and propagate the server validation errors to the client UI components

Data Paging

Changes for Hibernate 3.5 applications

if your application uses Hibernate 3 classes that are not available in Hibernate 4, for example, some of the validator or search classes, you may see ClassNotFoundExceptions when you deploy your application. If you encounter this problem, you can try one of two approaches: You may be able to resolve the issue by copying the specific Hibernate 3 JARs containing those classes into the application "/lib" directory or by adding them to the classpath using some other method. In some cases this may result in ClassCastExceptions or other class loading issues due to the mixed use of the Hibernate versions, so you will need to use the second approach. You need to tell the server to use only the Hibernate 3 libraries and you will need to add exclusions for the Hibernate 4 libraries. Details on how to do this are described here: JPA Reference Guide.

In previous versions of the application server, the JCA data source configuration was defined in a file with a suffix of *-ds.xml. This file was then deployed in the server's deploy directory. The JDBC driver was copied to the server lib/ directory or packaged in the application's WEB-INF/lib/ directory. In AS7, this has all changed. You will no longer package the JDBC driver with the application or in the server/lib directory. The *-ds.xml file is now obsolete and the datasource configuration information is now defined in the standalone/configuration/standalone.xml or in the domain/configuration/domain.xml file. A JDBC 4-compliant driver can be installed as a deployment or as a core module. A driver that is JDBC 4-compliant contains a META-INF/services/java.sql.Driver file that specifies the driver class name. A driver that is not JDBC 4-compliant requires additional steps, as noted below.

DataSource Configuration

domain mode, the configuration file is the domain/configuration/domain.xml

standalone mode, you will configure the datasource in the standalone/configuration/standalone.xml

MySQL datasource element:

        <connection-url>jdbc:mysql://localhost:3306/YourApplicationURL</connection-url>        <driver-class> com.mysql.jdbc.Driver </driver-class>        <driver> mysql-connector-java-5.1.15.jar </driver>

       <security>            <user-name> USERID </user-name>            <password> PASSWORD</password>        </security>

example of the driver element for driver that is not JDBC 4-compliant. The driver-class must be specified since it there is no META-INF/services/java.sql.Driver file that specifies the driver class name.

 <driver-class>com.mysql.jdbc.Driver</driver-class>

JDBC driver can be installed into the container in one of two ways: either as a deployment or as a core module

Install the JDBC driver

Install the JDBC driver as a deployment

In AS7 standalone mode, you simply copy the JDBC 4-compliant JAR into the AS7_HOME/standalone/deployments directory

example of a MySQL JDBC driver installed as a deployment:     AS7_HOME/standalone/deployments/mysql-connector-java-5.1.15.jar

It is perfect valid to introduce a dedicated DTO to adapt an incompatible domain layer

JSR-303 (“Bean Validation”) ActionScript3 framework for form validation

validation framework is a specific adaptation of the JSR-303 (Bean Validation) specification to Flex: like its Java counterpart, it relies on validation annotations placed on bean properties and provides an engine API that lets you validate your forms without writing by hand a specific validator for each of your input fields

code generation tools provided by GraniteDS so that when you write your Java entity bean with validation annotations, they are automatically replicated in your ActionScript3 beans

problem with LCDS is mainly that it promotes a strict “client / server” architecture, with – roughly speaking – a heavy Flex client application connected to a server almost reduced to a database frontend

big majority of  these organizations use BlazeDS, a free and open-source subset of LCDS

need more advanced mechanisms than just Remoting start looking for open-source libraries to enable deeper integrations with the Java business layer, and GraniteDS is for sure the most popular project

“Flex Data Services” (now renamed to “Live Cycle Data Services”)

Flex Data Services seemed too “client-centric”

for GraniteDS users keeping their Java domain model and ActionScript3 domain model in sync via Gas3, the constraints are kept in sync

a couple of gotchas to be aware of

the constraint implementation is in the same class as the constraint declaration (not a problem in a dynamic language) @Pattern has a sightly different semantic because the regexp engine in Flex is a bit different. instead of the features provided by ConstraintValidatorContext, you can define a properties attribute in your constraints to make it belong to several sub-properties. not as flexible but good enough in many cases.

new entity has no id until it has been persisted to the database

take care that you have added the [Lazy] annotation to your Flex metadata compilation configuration