Error when Eclipse started and now my package explorer is empty

Question

I'm currently learning Java, using a combination of the Head First Java book and Eclipse. Everything was going well until tonight!

When I started up Eclipse tonight, I saw an error message which I didn't pay attention to (I know! I know!) and acknowledged after which the project explorer was empty where it used to contain my Head First project!

After a quick "google" I found the workspace.metadata.log and the errors are shown below.

The version of Eclipse I am using is: 20100218-1602 and the only plugin that I use is egit.

Any help would be much appreciated.

!SESSION 2010-06-08 19:24:33.841 -----------------------------------------------
eclipse.buildId=unknown
java.version=1.5.0_22
java.vendor=Sun Microsystems Inc.
BootLoader constants: OS=win32, ARCH=x86, WS=win32, NL=en_GB
Framework arguments:  -product org.eclipse.epp.package.java.product
Command-line arguments:  -os win32 -ws win32 -arch x86 -product org.eclipse.epp.package.java.product

!ENTRY org.eclipse.ui.workbench 4 2 2010-06-08 19:24:36.475
!MESSAGE Problems occurred when invoking code from plug-in: "org.eclipse.ui.workbench".
!STACK 1
org.eclipse.ui.WorkbenchException: Content is not allowed in prolog.
    at org.eclipse.ui.XMLMemento.createReadRoot(XMLMemento.java:121)
    at org.eclipse.ui.XMLMemento.createReadRoot(XMLMemento.java:64)
    at org.eclipse.ui.internal.Workbench$49.run(Workbench.java:1895)
    at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
    at org.eclipse.ui.internal.Workbench.restoreState(Workbench.java:1890)
    at org.eclipse.ui.internal.WorkbenchConfigurer.restoreState(WorkbenchConfigurer.java:183)
    at org.eclipse.ui.application.WorkbenchAdvisor$1.run(WorkbenchAdvisor.java:781)
Caused by: org.xml.sax.SAXParseException: Content is not allowed in prolog.
    at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:264)
    at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:292)
    at org.eclipse.ui.XMLMemento.createReadRoot(XMLMemento.java:94)
    ... 6 more
!SUBENTRY 1 org.eclipse.ui 4 0 2010-06-08 19:24:36.475
!MESSAGE Content is not allowed in prolog.
!STACK 0
org.xml.sax.SAXParseException: Content is not allowed in prolog.
    at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:264)
    at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:292)
    at org.eclipse.ui.XMLMemento.createReadRoot(XMLMemento.java:94)
    at org.eclipse.ui.XMLMemento.createReadRoot(XMLMemento.java:64)
    at org.eclipse.ui.internal.Workbench$49.run(Workbench.java:1895)
    at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
    at org.eclipse.ui.internal.Workbench.restoreState(Workbench.java:1890)
    at org.eclipse.ui.internal.WorkbenchConfigurer.restoreState(WorkbenchConfigurer.java:183)
    at org.eclipse.ui.application.WorkbenchAdvisor$1.run(WorkbenchAdvisor.java:781)
!SUBENTRY 1 org.eclipse.ui 4 0 2010-06-08 19:24:36.475
!MESSAGE Content is not allowed in prolog.
!STACK 0
org.xml.sax.SAXParseException: Content is not allowed in prolog.
    at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:264)
    at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:292)
    at org.eclipse.ui.XMLMemento.createReadRoot(XMLMemento.java:94)
    at org.eclipse.ui.XMLMemento.createReadRoot(XMLMemento.java:64)
    at org.eclipse.ui.internal.Workbench$49.run(Workbench.java:1895)
    at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
    at org.eclipse.ui.internal.Workbench.restoreState(Workbench.java:1890)
    at org.eclipse.ui.internal.WorkbenchConfigurer.restoreState(WorkbenchConfigurer.java:183)
    at org.eclipse.ui.application.WorkbenchAdvisor$1.run(WorkbenchAdvisor.java:781)

!ENTRY org.eclipse.jdt.ui 4 10001 2010-06-08 19:24:41.442
!MESSAGE Internal Error
!STACK 1
org.eclipse.jdt.internal.ui.JavaUIException: Problems reading information from XML 'OpenTypeHistory.xml'
    at org.eclipse.jdt.internal.corext.util.History.createException(History.java:70)
    at org.eclipse.jdt.internal.corext.util.History.load(History.java:257)
    at org.eclipse.jdt.internal.corext.util.History.load(History.java:166)
    at org.eclipse.jdt.internal.corext.util.OpenTypeHistory.<init>(OpenTypeHistory.java:199)
    at org.eclipse.jdt.internal.corext.util.OpenTypeHistory.getInstance(OpenTypeHistory.java:185)
    at org.eclipse.jdt.internal.ui.JavaPlugin.initializeAfterLoad(JavaPlugin.java:381)
    at org.eclipse.jdt.internal.ui.InitializeAfterLoadJob$RealJob.run(InitializeAfterLoadJob.java:36)
    at org.eclipse.core.internal.jobs.Worker.run(Worker.java:55)
Caused by: org.xml.sax.SAXParseException: Content is not allowed in prolog.
    at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:264)
    at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:292)
    at org.eclipse.jdt.internal.corext.util.History.load(History.java:255)
    ... 6 more
!SUBENTRY 1 org.eclipse.jdt.ui 4 4 2010-06-08 19:24:41.442
!MESSAGE Problems reading information from XML 'OpenTypeHistory.xml'
!STACK 0
org.xml.sax.SAXParseException: Content is not allowed in prolog.
    at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:264)
    at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:292)
    at org.eclipse.jdt.internal.corext.util.History.load(History.java:255)
    at org.eclipse.jdt.internal.corext.util.History.load(History.java:166)
    at org.eclipse.jdt.internal.corext.util.OpenTypeHistory.<init>(OpenTypeHistory.java:199)
    at org.eclipse.jdt.internal.corext.util.OpenTypeHistory.getInstance(OpenTypeHistory.java:185)
    at org.eclipse.jdt.internal.ui.JavaPlugin.initializeAfterLoad(JavaPlugin.java:381)
    at org.eclipse.jdt.internal.ui.InitializeAfterLoadJob$RealJob.run(InitializeAfterLoadJob.java:36)
    at org.eclipse.core.internal.jobs.Worker.run(Worker.java:55)

!ENTRY org.eclipse.jdt.ui 4 10001 2010-06-08 19:24:50.435
!MESSAGE Internal Error
!STACK 1
org.eclipse.jdt.internal.ui.JavaUIException: Problems reading information from XML 'QualifiedTypeNameHistory.xml'
    at org.eclipse.jdt.internal.corext.util.History.createException(History.java:70)
    at org.eclipse.jdt.internal.corext.util.History.load(History.java:257)
    at org.eclipse.jdt.internal.corext.util.History.load(History.java:166)
    at org.eclipse.jdt.internal.corext.util.QualifiedTypeNameHistory.<init>(QualifiedTypeNameHistory.java:33)
    at org.eclipse.jdt.internal.corext.util.QualifiedTypeNameHistory.getDefault(QualifiedTypeNameHistory.java:26)
    at org.eclipse.jdt.internal.ui.JavaPlugin.stop(JavaPlugin.java:602)
    at org.eclipse.osgi.framework.internal.core.BundleContextImpl$2.run(BundleContextImpl.java:843)
    at java.security.AccessController.doPrivileged(Native Method)
    at org.eclipse.osgi.framework.internal.core.BundleContextImpl.stop(BundleContextImpl.java:836)
    at org.eclipse.osgi.framework.internal.core.BundleHost.stopWorker(BundleHost.java:474)
    at org.eclipse.osgi.framework.internal.core.AbstractBundle.suspend(AbstractBundle.java:546)
    at org.eclipse.osgi.framework.internal.core.Framework.suspendBundle(Framework.java:1098)
    at org.eclipse.osgi.framework.internal.core.StartLevelManager.decFWSL(StartLevelManager.java:593)
    at org.eclipse.osgi.framework.internal.core.StartLevelManager.doSetStartLevel(StartLevelManager.java:261)
    at org.eclipse.osgi.framework.internal.core.StartLevelManager.shutdown(StartLevelManager.java:216)
    at org.eclipse.osgi.framework.internal.core.InternalSystemBundle.suspend(InternalSystemBundle.java:266)
    at org.eclipse.osgi.framework.internal.core.Framework.shutdown(Framework.java:685)
    at org.eclipse.osgi.framework.internal.core.Framework.close(Framework.java:583)
    at org.eclipse.core.runtime.adaptor.EclipseStarter.shutdown(EclipseStarter.java:409)
    at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:200)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:592)
    at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:559)
    at org.eclipse.equinox.launcher.Main.basicRun(Main.java:514)
    at org.eclipse.equinox.launcher.Main.run(Main.java:1311)
Caused by: org.xml.sax.SAXParseException: Content is not allowed in prolog.
    at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:264)
    at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:292)
    at org.eclipse.jdt.internal.corext.util.History.load(History.java:255)
    ... 25 more
!SUBENTRY 1 org.eclipse.jdt.ui 4 4 2010-06-08 19:24:50.435
!MESSAGE Problems reading information from XML 'QualifiedTypeNameHistory.xml'
!STACK 0
org.xml.sax.SAXParseException: Content is not allowed in prolog.
    at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:264)
    at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:292)
    at org.eclipse.jdt.internal.corext.util.History.load(History.java:255)
    at org.eclipse.jdt.internal.corext.util.History.load(History.java:166)
    at org.eclipse.jdt.internal.corext.util.QualifiedTypeNameHistory.<init>(QualifiedTypeNameHistory.java:33)
    at org.eclipse.jdt.internal.corext.util.QualifiedTypeNameHistory.getDefault(QualifiedTypeNameHistory.java:26)
    at org.eclipse.jdt.internal.ui.JavaPlugin.stop(JavaPlugin.java:602)
    at org.eclipse.osgi.framework.internal.core.BundleContextImpl$2.run(BundleContextImpl.java:843)
    at java.security.AccessController.doPrivileged(Native Method)
    at org.eclipse.osgi.framework.internal.core.BundleContextImpl.stop(BundleContextImpl.java:836)
    at org.eclipse.osgi.framework.internal.core.BundleHost.stopWorker(BundleHost.java:474)
    at org.eclipse.osgi.framework.internal.core.AbstractBundle.suspend(AbstractBundle.java:546)
    at org.eclipse.osgi.framework.internal.core.Framework.suspendBundle(Framework.java:1098)
    at org.eclipse.osgi.framework.internal.core.StartLevelManager.decFWSL(StartLevelManager.java:593)
    at org.eclipse.osgi.framework.internal.core.StartLevelManager.doSetStartLevel(StartLevelManager.java:261)
    at org.eclipse.osgi.framework.internal.core.StartLevelManager.shutdown(StartLevelManager.java:216)
    at org.eclipse.osgi.framework.internal.core.InternalSystemBundle.suspend(InternalSystemBundle.java:266)
    at org.eclipse.osgi.framework.internal.core.Framework.shutdown(Framework.java:685)
    at org.eclipse.osgi.framework.internal.core.Framework.close(Framework.java:583)
    at org.eclipse.core.runtime.adaptor.EclipseStarter.shutdown(EclipseStarter.java:409)
    at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:200)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:592)
    at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:559)
    at org.eclipse.equinox.launcher.Main.basicRun(Main.java:514)
    at org.eclipse.equinox.launcher.Main.run(Main.java:1311)

Answer 1

Did you shut down eclipse properly last time? I would just go ahead and create a new workspace and then import my project files in it. Better invest time in learning rather than figuring out what's wrong with eclipse :-)