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Archive for the ‘Eclipse’ Category

Install java 8, changing the versions and set up eclipse

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1. Install java 8

	$ sudo add-apt-repository ppa:webupd8team/java
	$ sudo apt-get update
	$ sudo apt-get install oracle-java8-installer

2. Verify the java version by using the following command

	$ java -version

3. You can set the default version by using the below command

	sudo apt-get install oracle-java8-set-default

4. Changing the java version when there are multiple versions.
4.1 Check the avilable java versions

	$ sudo update-alternatives --display java

	namal@namal:~$ sudo update-alternatives --display java
	[sudo] password for namal: 
	java - auto mode
	  link currently points to /usr/lib/jvm/java-8-oracle/jre/bin/java
	/usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java - priority 1071
	  slave java.1.gz: /usr/lib/jvm/java-7-openjdk-amd64/jre/man/man1/java.1.gz
	/usr/lib/jvm/java-8-oracle/jre/bin/java - priority 1072
	  slave java.1.gz: /usr/lib/jvm/java-8-oracle/man/man1/java.1.gz
	Current 'best' version is '/usr/lib/jvm/java-8-oracle/jre/bin/java'.

4.2 Config to use another java version

	$ sudo update-alternatives --config java

	namal@namal:~$ sudo update-alternatives --config java
	There are 2 choices for the alternative java (providing /usr/bin/java).

	  Selection    Path                                            Priority   Status
	* 0            /usr/lib/jvm/java-8-oracle/jre/bin/java          1072      auto mode
	  1            /usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java   1071      manual mode
	  2            /usr/lib/jvm/java-8-oracle/jre/bin/java          1072      manual mode

	Press enter to keep the current choice[*], or type selection number: 

4.3 Double check the java version

	$ java -version

	namal@namal:~$ java -version
	java version "1.8.0_91"
	Java(TM) SE Runtime Environment (build 1.8.0_91-b14)
	Java HotSpot(TM) 64-Bit Server VM (build 25.91-b14, mixed mode)

5. Change the java version using by the IDE ( eg: eclipse)





Written by Namal Fernando

June 16, 2016 at 6:59 am

Posted in Eclipse, Java, Linux, TroubleShooting

Tagged with , ,

Import Project from Remote Repository to the eclipse

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1. Go to [File] > [Import]


Select project from Git (type “git” in the search field if needed)

{Git} > {Project from Git} > [ Next ]


Click on [Clone URI] and hit [Next]


2. Copy the Cloned URL from remote GIT repository.


3. Paste it in the URI area in eclipse window. (Of course you need the authentication details)


It will get the branch information. Select a branch (or master), click [Next]

Configure the local storage location for the Project.

Screenshot from 2015-04-10 07:50:33

After this step it will take you to the same path that can be followed to import a project from local git repository.

Written by Namal Fernando

April 10, 2015 at 7:54 am

Posted in Eclipse, GIT

Tagged with ,

How to commit a file to the remote git repository

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1. Commit it to the local repository

Right Click on the file [Team] > [Commit]

Add the Commit message and Hit [Commit]. (You can so this also by Right Click on the local repository in Git view)

Screenshot from 2015-04-10 07:17:19

2. Go to the local git repository

cd /rezsystem/workspace/demo-parsers

3. Just Push it! (Of course, it will ask the user name and password for the remote repo)

$ git push

Reference :

Written by Namal Fernando

April 10, 2015 at 7:18 am

Posted in Eclipse, GIT

Tagged with

How to import a GIT project from local Git repositories to the eclipse

with 2 comments

Method 1

Go to [File] > [Import]


Select project from Git (type “git” in the search field if needed)

{Git} > {Project from Git} > [ Next ]


Select Existing local repository (There’s an option also to get it directly from the Git repository too)


Select a Git repository

Select a Git repository from the list. (Or you can add an exisiting Git project to the list using the [Add] button and then select from there)


Just click [Next]


Finally [Finish] (as usually ūüėČ ). Here in the screenshot it is not selected to add and Finish is disabled since I have already imported it.


Or You can directly import from the Git perspective by Right Click on the relevant Git Repository and click on [Import Projects..]


Written by Namal Fernando

April 10, 2015 at 7:08 am

Posted in Eclipse, GIT

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How to Add Existing local Git repositories to the eclipse view

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1. Open GIT perspective in eclipse
GoTo [Window] > {Open Perspective} > [Other]


Select [Git] > [OK]

This will take the Git Repositories view with the perspective to the eclipse.

2. Add Existing Git repositories
Click on the [Git and + mark] icon with the tooltip saying “Add Existing local Git repositories to this view”.

Browse the project converted to the Git and hit [OK]

In the big white textArea the .git with yellow icon will be selected (In the screen shot it is not there since the project is already added. Feel a bit lazy to create another and add ūüėČ )

Then it will add the project to the git repo view


If you can see the navigator, it will be also in there with the GIT information in square brackets.


If your project is not yet opened in eclipse…
Check post on How to import a GIT project from local Git repositories to the eclipse

Written by Namal Fernando

April 10, 2015 at 6:45 am

Posted in Eclipse, GIT

Tagged with ,

Linking eclipse debugging with a remote jetty application

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1. Start jetty with the agent.

 java -Xdebug -agentlib:jdwp=transport=dt_socket,address=9999,server=y,suspend=n -jar start.jar

This port (9999) will be the port that expose the VM to eclipse.

2. It will start like this :

It must start with something like “Listening for transport dt_socket at address: 9999” if the remote agent started successfully.

namal@namal:/rezsystem/aventura/jetty-distribution-9.2.6.v20141205$ java -Xdebug -agentlib:jdwp=transport=dt_socket,address=9999,server=y,suspend=n -jar start.jar
 Listening for transport dt_socket at address: 9999
 2015-02-07 19:14:33.756:INFO::main: Logging initialized @1139ms
 2015-02-07 19:14:33.983:WARN:oejs.HomeBaseWarning:main: This instance of Jetty is not running from a separate {jetty.base} directory, this is not recommended. See documentation at
 2015-02-07 19:14:34.214:INFO:oejs.Server:main: jetty-9.2.6.v20141205
 2015-02-07 19:14:34.241:INFO:oejdp.ScanningAppProvider:main: Deployment monitor [file:/rezsystem/aventura/jetty-distribution-9.2.6.v20141205/webapps/] at interval 1
 2015-02-07 19:14:34.968:INFO:oejsh.ContextHandler:main: Started o.e.j.w.WebAppContext@114a0de{/jsp,file:/rezsystem/aventura/jetty-distribution-9.2.6.v20141205/webapps/jsp/,AVAILABLE}{/jsp}
 2015-02-07 19:14:35.230:INFO:oejsh.ContextHandler:main: Started o.e.j.w.WebAppContext@deaa44{/test-java,file:/tmp/jetty-,AVAILABLE}{/test-java.war}
 2015-02-07 19:14:35.567:INFO:oejsh.ContextHandler:main: Started o.e.j.w.WebAppContext@b6b7e3{/Connectors,file:/tmp/jetty-,AVAILABLE}{/Connectors.war}
 2015-02-07 19:14:35.830:INFO:oejsh.ContextHandler:main: Started o.e.j.w.WebAppContext@55de3b{/LoginExample,file:/tmp/jetty-,AVAILABLE}{/LoginExample.war}
 2015-02-07 19:14:35.880:INFO:oejs.ServerConnector:main: Started ServerConnector@db16d7{HTTP/1.1}{}
 2015-02-07 19:14:35.880:INFO:oejs.Server:main: Started @3263ms

3. Start Remote Debug

[Run] Debug As > [Debug Configurations…]


[Remote Java Application] > TestClassName

  • Project – This will be mentioned to initiate the debug points. It will not link with a particular project, but with the entire eclipse. it will ask for the particular project if the source couldn’t be located successfully.
  • Host – This may be a localhost or a remote IP
  • Port – This is the port that the VM agent was configured.



4. Launch the Java application.

5. Trouble shooting and improvements.

If the eclipse can’t list the source for the remotely executing class, it will ask you to select the source. You can mention it using the Attaching the source as a Java Project or a relevant other option.

References :

Written by Namal Fernando

February 8, 2015 at 10:28 am

Posted in Eclipse, Java

Tagged with , ,

How to recover eclipse?

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Follow this if your eclipse got crashed.

  • Delete the .lock file in the workspace/.metadata folder and restart the IDE
  • If this is not working delete the .snap file in the workspace/.metadata/.plugins/org.eclipse.core.resources and restart the IDE
  • If this is also not working
    • cd .metadata/.plugins
    • mv org.eclipse.core.resources org.eclipse.core.resources.bak
    • Start eclipse. (It should show an error message or an empty workspace because no project is found.)
    • Close all open editors tabs.
    • Exit eclipse.
    • rm -rf org.eclipse.core.resources (Delete the newly created directory.)
    • mv org.eclipse.core.resources.bak/ org.eclipse.core.resources (Restore the original directory.)
    • Start eclipse and start working.

More about the .lock

Eclipse comes with a locking mechanism that is on a ‘per workspace’ basis to ensure that there is no data corruption; only one Eclipse instance can operate on a particular workspace at a time, and as such each workspace is locked while it is open for business.

So… how do you break in to Eclipse when you leave your keys on the dresser? Well, it’s actually quite simple. When a workspace is brought up by a particular instance, that Eclipse instance will produce a ‘¬†.lock¬†‘ file and store it in a special folder for that workspace. Each workspace captures unique settings in a ‘.metadata¬†‘ folder. As a side note, this is also where the unique Eclipse workspace settings are stored.

If you are on Eclipse 2.1, to get back in to Eclipse so you can do your needed work, simply delete your ‘¬†[Workspace Home]/.metadata/.lock¬†‘ file.

As of Eclipse 3.0, however, the existence of the file is no longer the relevant state. The¬†good¬†news is that reserved file locks should happen a lot less now due to the nature of the locking mechanism. The bad news is it is somewhat less apparent how to unlock the environment if something¬†does¬†go wrong. Eclipse 3.0 will attempt to use an operating system file lock on the¬†.lock¬†file (file lock on the lock file, that’s a mouthful). If, for some reason, Eclipse cannot lock this file, in 99% of the cases simply restarting your OS will clear up any file locks or file handles that may be in place. It also doesn’t hurt to delete the file, but chances are if you can delete the file, Eclipse could lock it – so this probably isn’t a plausible solution.

The remaining 1% of the cases are more than likely caused because you are fiddling with folder permissions, and Eclipse can’t write to the¬†.metadata¬†folder. Bad user!

More About .snap file

It looks like your eclipse platform is crashing quite often. Because otherwise, the snapshot files should not be there while the platform is not running. As the referenced page in roe’s comment explains, they are just needed for crash recovery and are deleted during normal shutdown of the platform. Deleting them will make eclipse think, that no crash occurred but then it can’t recover and you may have to refresh/rebuild your workspace (which may take the same time).

I’d not delete those files except eclipse won’t recover from a crash. Have a look at the eclipse workspace and platform log files if you have troubles with some plugins and fight the problem from this side (updating plugins or sending error reports) instead of deleting those files.

Written by Namal Fernando

November 6, 2013 at 4:25 pm

Posted in Eclipse

Tagged with , ,

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