How do you launch this copy of Eclipse? Is it forcing a specific workspace directory with the -data switch?

did you download and install eclipse from www.eclipse.org ?

Do you have an eclipse.ini file in the directory where the eclipse executable lives? What are its contents?

-startup
plugins/org.eclipse.equinox.launcher_1.3.0.v20140415-2008.jar
--launcher.library
plugins/org.eclipse.equinox.launcher.gtk.linux.x86_64_1.1.200.v20140603-1326
-product
org.eclipse.epp.package.jee.product
--launcher.defaultAction
openFile
-showsplash
org.eclipse.platform
--launcher.XXMaxPermSize
256m
--launcher.defaultAction
openFile
--launcher.appendVmargs
-startup
/opt/eclipse/plugins/org.eclipse.equinox.launcher_1.3.0.v20140415-2008.jar
--launcher.library
/opt/eclipse/plugins/org.eclipse.equinox.launcher.gtk.linux.x86_64_1.1.200.v20140603-1326
-vmargs
-Dosgi.requiredJavaVersion=1.6
-XX:MaxPermSize=256m
-Xms40m
-Xmx512m

Are you now, or have you ever, run it as root?

Download another copy from eclipse.org, keep it somewhere under your home directory, and run that one? And never as root.

Can you be certain that you're running the copy of Eclipse that you think you are (for example, using "which eclipse" and/or going to the folder where your intended Eclipse lives and running "./eclipse)?"

$>which eclipse
/usr/bin/eclipse
$>ls -Al /usr/bin | grep eclipse
lrwxrwxrwx 1 root   root          20 set 24  2013 eclipse -> /opt/eclipse/eclipse

...

*** Date: Wednesday, October 15, 2014 at 10:00:37 PM Central European Summer Time

*** Platform Details:

*** System properties:
applicationXMI=org.eclipse.ui.workbench/LegacyIDE.e4xmi
awt.toolkit=sun.awt.X11.XToolkit
eclipse.application=org.eclipse.ui.ide.workbench
eclipse.buildId=4.4.1.M20140925-0400
eclipse.commands=-data
/media/Data/Personal Folder/Programming/Eclipse/ComputazionePervasiva
-os
linux
-ws
gtk
-arch
x86_64
-showsplash
/opt/eclipse//plugins/org.eclipse.platform_4.4.0.v20140925-0400/splash.bmp
-launcher
/opt/eclipse/eclipse
-name
Eclipse
--launcher.library
/opt/eclipse/plugins/org.eclipse.equinox.launcher.gtk.linux.x86_64_1.1.200.v20140603-1326/eclipse_1605.so
-startup
/opt/eclipse/plugins/org.eclipse.equinox.launcher_1.3.0.v20140415-2008.jar
--launcher.appendVmargs
-exitdata
2e8018
-product
org.eclipse.epp.package.jee.product
-vm
/usr/bin/java
eclipse.home.location=file:/opt/eclipse/
eclipse.launcher=/opt/eclipse/eclipse
eclipse.launcher.name=Eclipse
eclipse.p2.data.area=@config.dir/../p2/
eclipse.p2.profile=epp.package.jee
eclipse.product=org.eclipse.epp.package.jee.product
eclipse.startTime=1413385294028
eclipse.stateSaveDelayInterval=30000
eclipse.vm=/usr/bin/java
eclipse.vmargs=-Dosgi.requiredJavaVersion=1.6
-XX:MaxPermSize=256m
-Xms40m
-Xmx512m
-jar
/opt/eclipse/plugins/org.eclipse.equinox.launcher_1.3.0.v20140415-2008.jar
equinox.use.ds=true
file.encoding=UTF-8
file.encoding.pkg=sun.io
file.separator=/
gosh.args=--nointeractive
guice.disable.misplaced.annotation.check=true
java.awt.graphicsenv=sun.awt.X11GraphicsEnvironment
java.awt.printerjob=sun.print.PSPrinterJob
java.class.path=/opt/eclipse/plugins/org.eclipse.equinox.launcher_1.3.0.v20140415-2008.jar
java.class.version=52.0
java.endorsed.dirs=/usr/lib/jvm/java-8-oracle/jre/lib/endorsed
java.ext.dirs=/usr/lib/jvm/java-8-oracle/jre/lib/ext:/usr/java/packages/lib/ext
java.home=/usr/lib/jvm/java-8-oracle/jre
java.io.tmpdir=/tmp
java.library.path=/usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib
java.runtime.name=Java(TM) SE Runtime Environment
java.runtime.version=1.8.0_20-b26
java.specification.name=Java Platform API Specification
java.specification.vendor=Oracle Corporation
java.specification.version=1.8
java.vendor=Oracle Corporation
java.vendor.url=http://java.oracle.com/
java.vendor.url.bug=http://bugreport.sun.com/bugreport/
java.version=1.8.0_20
java.vm.info=mixed mode
java.vm.name=Java HotSpot(TM) 64-Bit Server VM
java.vm.specification.name=Java Virtual Machine Specification
java.vm.specification.vendor=Oracle Corporation
java.vm.specification.version=1.8
java.vm.vendor=Oracle Corporation
java.vm.version=25.20-b23
line.separator=

org.apache.commons.logging.Log=org.apache.commons.logging.impl.NoOpLog
org.eclipse.debug.ui.breakpoints.toggleFactoriesUsed=true
org.eclipse.equinox.launcher.splash.location=/opt/eclipse//plugins/org.eclipse.platform_4.4.0.v20140925-0400/splash.bmp
org.eclipse.equinox.simpleconfigurator.configUrl=file:org.eclipse.equinox.simpleconfigurator/bundles.info
org.eclipse.m2e.log.dir=/media/Data/Personal Folder/Programming/Eclipse/ComputazionePervasiva/.metadata/.plugins/org.eclipse.m2e.logback.configuration
org.eclipse.swt.browser.DefaultType=mozilla
org.eclipse.swt.browser.MozillaFactoriesRegistered=true
org.eclipse.swt.browser.XULRunnerInitialized=true
org.eclipse.swt.browser.XULRunnerPath=/opt/eclipse/plugins/org.mozilla.xulrunner.gtk.linux.x86_64_1.9.2.19pre/xulrunner
org.eclipse.swt.internal.gtk.useCairo=true
org.eclipse.update.reconcile=false
org.jboss.tools.resolved.remote.properties=examples.categories.url|jbosstools|4.2=http://download.jboss.org/jbosstools/examples/project-examples-category-4.2.xml
maven.examples.url|jbosstools|4.2=http://download.jboss.org/jbosstools/examples/project-examples-maven-4.2.GA.xml
jboss.discovery.site.url|jbosstools|4.2.0=http://download.jboss.org/jbosstools/updates/development/luna/central/core/
jboss.discovery.directory.url|jbosstools|4.2.0=http://download.jboss.org/jbosstools/updates/development/luna/jbosstools-directory.xml
buzz.feed.url=http://planet.jboss.org/feeds/buzz
jboss.discovery.earlyaccess.list.url|jbosstools|4.2.0=http://download.jboss.org/jbosstools/updates/development/luna/jbosstools-earlyaccess.properties
jboss.discovery.earlyaccess.site.url|jbosstools|4.2.0=http://download.jboss.org/jbosstools/earlyaccess/development/luna/
community.examples.url|jbosstools|4.2=http://download.jboss.org/jbosstools/examples/project-examples-community-4.2.Beta2.xml
portal.examples.url|jbosstools|4.2=http://download.jboss.org/gatein/quickstarts/jboss-portal-6.2/project-examples-jboss-portal6.2-jbds8.0-001.xml
featured.examples.url|jbosstools|4.2=http://download.jboss.org/jbosstools/examples/project-examples-shared-4.2.GA.xml

org.osgi.framework.executionenvironment=OSGi/Minimum-1.0,OSGi/Minimum-1.1,OSGi/Minimum-1.2,JavaSE/compact1-1.8,JavaSE/compact2-1.8,JavaSE/compact3-1.8,JRE-1.1,J2SE-1.2,J2SE-1.3,J2SE-1.4,J2SE-1.5,JavaSE-1.6,JavaSE-1.7,JavaSE-1.8
org.osgi.framework.language=en
org.osgi.framework.os.name=Linux
org.osgi.framework.os.version=3.13.0
org.osgi.framework.processor=x86-64
org.osgi.framework.system.capabilities=osgi.ee; osgi.ee="OSGi/Minimum"; version:List<Version>="1.0, 1.1, 1.2",osgi.ee; osgi.ee="JRE"; version:List<Version>="1.0, 1.1",osgi.ee; osgi.ee="JavaSE"; version:List<Version>="1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8",osgi.ee; osgi.ee="JavaSE/compact1"; version:List<Version>="1.8",osgi.ee; osgi.ee="JavaSE/compact2"; version:List<Version>="1.8",osgi.ee; osgi.ee="JavaSE/compact3"; version:List<Version>="1.8"
org.osgi.framework.system.packages=<...content trimmed...>
org.osgi.framework.uuid=2028c027-7c54-0014-1f28-9b8978f7b73a
org.osgi.framework.vendor=Eclipse
org.osgi.framework.version=1.8.0
org.osgi.supports.framework.extension=true
org.osgi.supports.framework.fragment=true
org.osgi.supports.framework.requirebundle=true
os.arch=amd64
os.name=Linux
os.version=3.13.0-37-generic
osgi.arch=x86_64
osgi.bundles=reference:file:org.eclipse.osgi.compatibility.state_1.0.1.v20140709-1414.jar,reference:file:org.eclipse.equinox.weaving.hook_1.1.100.weaving-hook-20140821.jar,reference:file:org.eclipse.fx.osgi_1.0.0.201408250501.jar,reference:file:org.eclipse.equinox.simpleconfigurator_1.1.0.v20131217-1203.jar@1:start
osgi.bundles.defaultStartLevel=4
osgi.compatibility.bootdelegation=true
osgi.configuration.area=file:/opt/eclipse/configuration/
osgi.configuration.area.default=null
osgi.framework=file:/opt/eclipse/plugins/org.eclipse.osgi_3.10.1.v20140909-1633.jar
osgi.framework.extensions=reference:file:org.eclipse.osgi.compatibility.state_1.0.1.v20140709-1414.jar,reference:file:org.eclipse.equinox.weaving.hook_1.1.100.weaving-hook-20140821.jar,reference:file:org.eclipse.fx.osgi_1.0.0.201408250501.jar
osgi.framework.shape=jar
osgi.framework.useSystemProperties=true
osgi.frameworkClassPath=., file:/opt/eclipse/plugins/org.eclipse.osgi.compatibility.state_1.0.1.v20140709-1414.jar, file:/opt/eclipse/plugins/org.eclipse.equinox.weaving.hook_1.1.100.weaving-hook-20140821.jar, file:/opt/eclipse/plugins/org.eclipse.fx.osgi_1.0.0.201408250501.jar
osgi.install.area=file:/opt/eclipse/
osgi.instance.area=file:/media/Data/Personal Folder/Programming/Eclipse/ComputazionePervasiva/
osgi.instance.area.default=file:/home/xxx/
osgi.logfile=/media/Data/Personal Folder/Programming/Eclipse/ComputazionePervasiva/.metadata/.log
osgi.nl=en_US
osgi.os=linux
osgi.requiredJavaVersion=1.6
osgi.splashLocation=/opt/eclipse//plugins/org.eclipse.platform_4.4.0.v20140925-0400/splash.bmp
osgi.splashPath=platform:/base/plugins/org.eclipse.platform
osgi.syspath=/opt/eclipse/plugins
osgi.tracefile=/media/Data/Personal Folder/Programming/Eclipse/ComputazionePervasiva/.metadata/trace.log
osgi.user.area=file:/home/xxx/user/
osgi.user.area.default=null
osgi.ws=gtk
path.separator=:
product.home=/opt/eclipse/plugins/org.jboss.tools.common.model_3.6.0.CR1-v20140829-2038-B51/
securerandom.source=file:/dev/./urandom
sun.arch.data.model=64
sun.boot.class.path=/usr/lib/jvm/java-8-oracle/jre/lib/resources.jar:/usr/lib/jvm/java-8-oracle/jre/lib/rt.jar:/usr/lib/jvm/java-8-oracle/jre/lib/sunrsasign.jar:/usr/lib/jvm/java-8-oracle/jre/lib/jsse.jar:/usr/lib/jvm/java-8-oracle/jre/lib/jce.jar:/usr/lib/jvm/java-8-oracle/jre/lib/charsets.jar:/usr/lib/jvm/java-8-oracle/jre/lib/jfr.jar:/usr/lib/jvm/java-8-oracle/jre/classes
sun.boot.library.path=/usr/lib/jvm/java-8-oracle/jre/lib/amd64
sun.cpu.endian=little
sun.cpu.isalist=
sun.desktop=gnome
sun.font.fontmanager=sun.awt.X11FontManager
sun.io.unicode.encoding=UnicodeLittle
sun.java.command=/opt/eclipse/plugins/org.eclipse.equinox.launcher_1.3.0.v20140415-2008.jar -data /media/Data/Personal Folder/Programming/Eclipse/ComputazionePervasiva -os linux -ws gtk -arch x86_64 -showsplash /opt/eclipse//plugins/org.eclipse.platform_4.4.0.v20140925-0400/splash.bmp -launcher /opt/eclipse/eclipse -name Eclipse --launcher.library /opt/eclipse/plugins/org.eclipse.equinox.launcher.gtk.linux.x86_64_1.1.200.v20140603-1326/eclipse_1605.so -startup /opt/eclipse/plugins/org.eclipse.equinox.launcher_1.3.0.v20140415-2008.jar --launcher.appendVmargs -exitdata 2e8018 -product org.eclipse.epp.package.jee.product -vm /usr/bin/java -vmargs -Dosgi.requiredJavaVersion=1.6 -XX:MaxPermSize=256m -Xms40m -Xmx512m -jar /opt/eclipse/plugins/org.eclipse.equinox.launcher_1.3.0.v20140415-2008.jar
sun.java.launcher=SUN_STANDARD
sun.jnu.encoding=UTF-8
sun.management.compiler=HotSpot 64-Bit Tiered Compilers
sun.os.patch.level=unknown
user.country=US
user.dir=/home/xxx
user.home=/home/xxx
user.language=en
user.name=xxx
user.timezone=Europe/Rome

These lines tell us that something in the way you launch Eclipse is specifying a workspace:

eclipse.commands=-data
/media/Data/Personal Folder/Programming/Eclipse/ComputazionePervasiva

The -data command instructs Eclipse to load that workspace and ignore the "Show workspace selection at start-up" setting.

So the question now is, what about the way you launch Eclipse is inserting that? One brutish way to find out would be to search your file system for that text (either "-data" or the name of the workspace that comes after it).

What you're saying and what what the evidence says (the configuration details you posted) are two different things. Which is it?

cd /opt/eclipse
./eclipse

$>./eclipse
Java HotSpot(TM) 64-Bit Server VM warning: ignoring option MaxPermSize=256m; support was removed in 8.0
org.eclipse.m2e.logback.configuration: The org.eclipse.m2e.logback.configuration bundle was activated before the state location was initialized.  Will retry after the state location is initialized.
org.eclipse.m2e.logback.configuration: Logback config file: /opt/eclipse/.metadata/.plugins/org.eclipse.m2e.logback.configuration/logback.1.5.0.20140606-0033.xml
org.eclipse.m2e.logback.configuration: SLF4J logger factory class: org.slf4j.helpers.SubstituteLoggerFactory
org.eclipse.m2e.logback.configuration: SLF4J logger factory class: org.slf4j.helpers.SubstituteLoggerFactory
org.eclipse.m2e.logback.configuration: Initializing logback
java.lang.ClassCastException: org.eclipse.osgi.internal.framework.EquinoxConfiguration$1 cannot be cast to java.lang.String
	at org.eclipse.m2e.logback.configuration.LogHelper.logJavaProperties(LogHelper.java:26)
	at org.eclipse.m2e.logback.configuration.LogPlugin.loadConfiguration(LogPlugin.java:189)
	at org.eclipse.m2e.logback.configuration.LogPlugin.configureLogback(LogPlugin.java:144)
	at org.eclipse.m2e.logback.configuration.LogPlugin.access$2(LogPlugin.java:107)
	at org.eclipse.m2e.logback.configuration.LogPlugin$1.run(LogPlugin.java:62)
	at java.util.TimerThread.mainLoop(Timer.java:555)
	at java.util.TimerThread.run(Timer.java:505)
[INFO] Setting property: classpath.resource.loader.class => 'org.codehaus.plexus.velocity.ContextClassLoaderResourceLoader'.
[INFO] Setting property: velocimacro.messages.on => 'false'.
[INFO] Setting property: resource.loader => 'classpath'.
[INFO] Setting property: resource.manager.logwhenfound => 'false'.
log4j:WARN No appenders could be found for logger (org.springsource.ide.eclipse.commons.core.templates.TemplateProcessor).
log4j:WARN Please initialize the log4j system properly.

*** Date: Sunday, October 19, 2014 at 9:37:59 PM Central European Summer Time

*** Platform Details:

*** System properties:
applicationXMI=org.eclipse.ui.workbench/LegacyIDE.e4xmi
awt.toolkit=sun.awt.X11.XToolkit
eclipse.application=org.eclipse.ui.ide.workbench
eclipse.buildId=4.4.1.M20140925-0400
eclipse.commands=-os
linux
-ws
gtk
-arch
x86_64
-showsplash
/opt/eclipse//plugins/org.eclipse.platform_4.4.0.v20140925-0400/splash.bmp
-launcher
/opt/eclipse/eclipse
-name
Eclipse
--launcher.library
/opt/eclipse/plugins/org.eclipse.equinox.launcher.gtk.linux.x86_64_1.1.200.v20140603-1326/eclipse_1605.so
-startup
/opt/eclipse/plugins/org.eclipse.equinox.launcher_1.3.0.v20140415-2008.jar
--launcher.appendVmargs
-exitdata
4064800c
-product
org.eclipse.epp.package.jee.product
-vm
/usr/bin/java
eclipse.home.location=file:/opt/eclipse/
eclipse.launcher=/opt/eclipse/eclipse
eclipse.launcher.name=Eclipse
eclipse.p2.data.area=@config.dir/../p2/
eclipse.p2.profile=epp.package.jee
eclipse.product=org.eclipse.epp.package.jee.product
eclipse.startTime=1413747456898
eclipse.stateSaveDelayInterval=30000
eclipse.vm=/usr/bin/java
eclipse.vmargs=-Dosgi.requiredJavaVersion=1.6
-XX:MaxPermSize=256m
-Xms40m
-Xmx512m
-jar
/opt/eclipse/plugins/org.eclipse.equinox.launcher_1.3.0.v20140415-2008.jar
equinox.use.ds=true
file.encoding=UTF-8
file.encoding.pkg=sun.io
file.separator=/
gosh.args=--nointeractive
guice.disable.misplaced.annotation.check=true
java.awt.graphicsenv=sun.awt.X11GraphicsEnvironment
java.awt.printerjob=sun.print.PSPrinterJob
java.class.path=/opt/eclipse/plugins/org.eclipse.equinox.launcher_1.3.0.v20140415-2008.jar
java.class.version=52.0
java.endorsed.dirs=/usr/lib/jvm/java-8-oracle/jre/lib/endorsed
java.ext.dirs=/usr/lib/jvm/java-8-oracle/jre/lib/ext:/usr/java/packages/lib/ext
java.home=/usr/lib/jvm/java-8-oracle/jre
java.io.tmpdir=/tmp
java.library.path=/usr/lib/nvidia-331/:/usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib
java.runtime.name=Java(TM) SE Runtime Environment
java.runtime.version=1.8.0_25-b17
java.specification.name=Java Platform API Specification
java.specification.vendor=Oracle Corporation
java.specification.version=1.8
java.vendor=Oracle Corporation
java.vendor.url=http://java.oracle.com/
java.vendor.url.bug=http://bugreport.sun.com/bugreport/
java.version=1.8.0_25
java.vm.info=mixed mode
java.vm.name=Java HotSpot(TM) 64-Bit Server VM
java.vm.specification.name=Java Virtual Machine Specification
java.vm.specification.vendor=Oracle Corporation
java.vm.specification.version=1.8
java.vm.vendor=Oracle Corporation
java.vm.version=25.25-b02
line.separator=

org.apache.commons.logging.Log=org.apache.commons.logging.impl.NoOpLog
org.eclipse.debug.ui.breakpoints.toggleFactoriesUsed=true
org.eclipse.equinox.launcher.splash.location=/opt/eclipse//plugins/org.eclipse.platform_4.4.0.v20140925-0400/splash.bmp
org.eclipse.equinox.simpleconfigurator.configUrl=file:org.eclipse.equinox.simpleconfigurator/bundles.info
org.eclipse.m2e.log.dir=/home/xxx/.metadata/.plugins/org.eclipse.m2e.logback.configuration
org.eclipse.swt.internal.gtk.useCairo=true
org.eclipse.update.reconcile=false
org.eclipse.update.resolution_url=
org.osgi.framework.executionenvironment=OSGi/Minimum-1.0,OSGi/Minimum-1.1,OSGi/Minimum-1.2,JavaSE/compact1-1.8,JavaSE/compact2-1.8,JavaSE/compact3-1.8,JRE-1.1,J2SE-1.2,J2SE-1.3,J2SE-1.4,J2SE-1.5,JavaSE-1.6,JavaSE-1.7,JavaSE-1.8
org.osgi.framework.language=en
org.osgi.framework.os.name=Linux
org.osgi.framework.os.version=3.13.0
org.osgi.framework.processor=x86-64
org.osgi.framework.system.capabilities=osgi.ee; osgi.ee="OSGi/Minimum"; version:List<Version>="1.0, 1.1, 1.2",osgi.ee; osgi.ee="JRE"; version:List<Version>="1.0, 1.1",osgi.ee; osgi.ee="JavaSE"; version:List<Version>="1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8",osgi.ee; osgi.ee="JavaSE/compact1"; version:List<Version>="1.8",osgi.ee; osgi.ee="JavaSE/compact2"; version:List<Version>="1.8",osgi.ee; osgi.ee="JavaSE/compact3"; version:List<Version>="1.8"
org.osgi.framework.system.packages=<content truncated>
org.osgi.framework.uuid=402fed61-c757-0014-1f16-ed19c45e2914
org.osgi.framework.vendor=Eclipse
org.osgi.framework.version=1.8.0
org.osgi.supports.framework.extension=true
org.osgi.supports.framework.fragment=true
org.osgi.supports.framework.requirebundle=true
os.arch=amd64
os.name=Linux
os.version=3.13.0-37-generic
osgi.arch=x86_64
osgi.bundles=reference:file:org.eclipse.osgi.compatibility.state_1.0.1.v20140709-1414.jar,reference:file:org.eclipse.equinox.weaving.hook_1.1.100.weaving-hook-20140821.jar,reference:file:org.eclipse.fx.osgi_1.0.0.201408150502.jar,reference:file:org.eclipse.equinox.simpleconfigurator_1.1.0.v20131217-1203.jar@1:start
osgi.bundles.defaultStartLevel=4
osgi.compatibility.bootdelegation=true
osgi.configuration.area=file:/opt/eclipse/configuration/
osgi.configuration.area.default=null
osgi.framework=file:/opt/eclipse/plugins/org.eclipse.osgi_3.10.1.v20140909-1633.jar
osgi.framework.extensions=reference:file:org.eclipse.osgi.compatibility.state_1.0.1.v20140709-1414.jar,reference:file:org.eclipse.equinox.weaving.hook_1.1.100.weaving-hook-20140821.jar,reference:file:org.eclipse.fx.osgi_1.0.0.201408150502.jar
osgi.framework.shape=jar
osgi.framework.useSystemProperties=true
osgi.frameworkClassPath=., file:/opt/eclipse/plugins/org.eclipse.osgi.compatibility.state_1.0.1.v20140709-1414.jar, file:/opt/eclipse/plugins/org.eclipse.equinox.weaving.hook_1.1.100.weaving-hook-20140821.jar, file:/opt/eclipse/plugins/org.eclipse.fx.osgi_1.0.0.201408150502.jar
osgi.install.area=file:/opt/eclipse/
osgi.instance.area=file:/home/xxx/
osgi.instance.area.default=file:/home/xxx/
osgi.logfile=/home/xxx/.metadata/.log
osgi.nl=en_US
osgi.os=linux
osgi.requiredJavaVersion=1.6
osgi.splashLocation=/opt/eclipse//plugins/org.eclipse.platform_4.4.0.v20140925-0400/splash.bmp
osgi.splashPath=platform:/base/plugins/org.eclipse.platform
osgi.syspath=/opt/eclipse/plugins
osgi.tracefile=/home/xxx/.metadata/trace.log
osgi.user.area=null
osgi.user.area.default=null
osgi.ws=gtk
path.separator=:
securerandom.source=file:/dev/./urandom
sun.arch.data.model=64
sun.boot.class.path=/usr/lib/jvm/java-8-oracle/jre/lib/resources.jar:/usr/lib/jvm/java-8-oracle/jre/lib/rt.jar:/usr/lib/jvm/java-8-oracle/jre/lib/sunrsasign.jar:/usr/lib/jvm/java-8-oracle/jre/lib/jsse.jar:/usr/lib/jvm/java-8-oracle/jre/lib/jce.jar:/usr/lib/jvm/java-8-oracle/jre/lib/charsets.jar:/usr/lib/jvm/java-8-oracle/jre/lib/jfr.jar:/usr/lib/jvm/java-8-oracle/jre/classes
sun.boot.library.path=/usr/lib/jvm/java-8-oracle/jre/lib/amd64
sun.cpu.endian=little
sun.cpu.isalist=
sun.desktop=gnome
sun.io.unicode.encoding=UnicodeLittle
sun.java.command=/opt/eclipse/plugins/org.eclipse.equinox.launcher_1.3.0.v20140415-2008.jar -os linux -ws gtk -arch x86_64 -showsplash /opt/eclipse//plugins/org.eclipse.platform_4.4.0.v20140925-0400/splash.bmp -launcher /opt/eclipse/eclipse -name Eclipse --launcher.library /opt/eclipse/plugins/org.eclipse.equinox.launcher.gtk.linux.x86_64_1.1.200.v20140603-1326/eclipse_1605.so -startup /opt/eclipse/plugins/org.eclipse.equinox.launcher_1.3.0.v20140415-2008.jar --launcher.appendVmargs -exitdata 4064800c -product org.eclipse.epp.package.jee.product -vm /usr/bin/java -vmargs -Dosgi.requiredJavaVersion=1.6 -XX:MaxPermSize=256m -Xms40m -Xmx512m -jar /opt/eclipse/plugins/org.eclipse.equinox.launcher_1.3.0.v20140415-2008.jar
sun.java.launcher=SUN_STANDARD
sun.jnu.encoding=UTF-8
sun.management.compiler=HotSpot 64-Bit Tiered Compilers
sun.os.patch.level=unknown
user.country=US
user.dir=/home/xxx
user.home=/home/xxx
user.language=en
user.name=xxx
user.timezone=Europe/Rome

It's not clear what you're trying now. The configuration details above do not include the -data option that loads a specific workspace; the info suggests that it was running on a workspace at /home/xxx/
Can you be more specific and detailed about what you're doing when you post these details, and what behavior you're observing?

1. I launch eclipse (without any further options)
   
2. -----it shows the anonymous workspace (no projects and so on)
   
3. I switch workspace File>Switch workspace>WhateverWorkspace
   
4. -----it shows the WhateverWorkspace