oracle sql developer crashes

Running Windows Server 2008 R2 Standard. I have updated JDK to 1.8.0_91 Running SQL Developer 4.1.3.

SQL Developer loads OK, and I can connect to a database and do selects, but when I start clicking around in the tree, it suddenly stops working.

Tried to collect debug information as described here: http://www.thatjeffsmith.com/archive/2012/06/how-to-collect-debug-info-for-oracle-sql-developer/

but the only output I get is this 1 line:

LOAD TIME : 320UsersCache.fillIn() time = 32  ret==null?: true

If I run this command: sqldeveloper -verbose

I get some more information, see further below.

What can I do to make this work? It has been working for several months, but suddenly one morning it stopped. Did not make any changes to anything, as far as I know (or remember). Maybe an update to Windows, not sure about that.

Output from sqldeveloper -verbose:

C:\oracle\sqldeveloper\sqldeveloper\bin>sqldeveloper -verbose

Processing Hotspot specific options
Processing Hotspot JDK 7 specific options
savedArg0 = C:\oracle\sqldeveloper\sqldeveloper\bin\sqldeveloper.exe
VM to launch c:\Program Files\Java\jdk1.8.0_91\jre\bin\server\jvm.dll
Restarting the launcher with the 64bit version
Reading exe header from jvm.dll, Machine=8664
Jvm is 64bit
Checking toplevel for C:\oracle\sqldeveloper\sqldeveloper\bin\..\..\ide\bin\launcher.dll = 0
About to relaunch with command line: C:\oracle\sqldeveloper\sqldeveloper\bin\sqldeveloper64.exe -verbose
Processing Hotspot specific options
Processing Hotspot JDK 7 specific options
savedArg0 = C:\oracle\sqldeveloper\sqldeveloper\bin\sqldeveloper64.exe
VM to launch c:\Program Files\Java\jdk1.8.0_91\jre\bin\server\jvm.dll
JNI Option: -Xbootclasspath/a:c:\Program Files\Java\jdk1.8.0_91\lib\tools.jar;c:\Program Files\Java\jdk1.8.0_91\lib\dt.jar
JNI Option: -Dsun.java2d.noddraw=true
JNI Option: -Dnetbeans.home=/oracle/sqldeveloper/netbeans/platform/
JNI Option: -Dnetbeans.logger.console=true
JNI Option: -Dexcluded.modules=org.eclipse.osgi
JNI Option: -Dide.cluster.dirs=/oracle/sqldeveloper/netbeans/fcpbridge/:/oracle/sqldeveloper/netbeans/ide/:/oracle/sqldeveloper/netbeans/../
JNI Option: -Xverify:none
JNI Option: -Doracle.ide.extension.HooksProcessingMode=LAZY
JNI Option: -Dorg.eclipse.equinox.simpleconfigurator.configUrl=file:bundles.info
JNI Option: -Dosgi.bundles.defaultStartLevel=1
JNI Option: -Dosgi.configuration.cascaded=false
JNI Option: -Dosgi.noShutdown=true
JNI Option: -Dorg.osgi.framework.bootdelegation=*
JNI Option: -Dosgi.parentClassloader=app
JNI Option: -Dosgi.locking=none
JNI Option: -Dosgi.contextClassLoaderParent=app
JNI Option: -Xbootclasspath/p:/oracle/sqldeveloper/rdbms/jlib/ojdi.jar
JNI Option: -Dosgi.classloader.type=parallel
JNI Option: -Dosgi.bundlefile.limit=500
JNI Option: -Dide.feedback-server=ide.us.oracle.com
JNI Option: -Djavax.xml.transform.TransformerFactory=oracle.ide.xml.switchable.SwitchableTransformerFactory
JNI Option: -Djavax.xml.stream.XMLInputFactory=com.ctc.wstx.stax.WstxInputFactory
JNI Option: -Djavax.xml.stream.util.XMLEventAllocator=oracle.ideimpl.xml.stream.XMLEventAllocatorImpl
JNI Option: -Doracle.ide.reportEDTViolations=bug
JNI Option: -Doracle.ide.reportEDTViolations.exceptionsfile=/oracle/sqldeveloper/ide/bin/swing-thread-violations.conf
JNI Option: -Xms128M
JNI Option: -Xmx800M
JNI Option: -Doracle.ide.IdeFrameworkCommandLineOptions=-clean,-console,-debugmode,-migrate,-migrate:,-nomigrate,-nonag,-nondebugmode,-noreopen,-nosplash,-role:,-su
JNI Option: -Dide.update.usage.servers=http://www.oracle.com/webfolder/technetwork/sqldeveloper/usage.xml
JNI Option: -Doracle.ide.util.AddinPolicyUtils.OVERRIDE_FLAG=true
JNI Option: -Dsun.java2d.ddoffscreen=false
JNI Option: -Dwindows.shell.font.languages=
JNI Option: -Doracle.ide.startup.features=sqldeveloper
JNI Option: -Doracle.ide.osgi.boot.api.OJStartupHook=oracle.dbtools.raptor.startup.HomeSupport
JNI Option: -Doracle.jdbc.mapDateToTimestamp=false
JNI Option: -Doracle.jdbc.autoCommitSpecCompliant=false
JNI Option: -Doracle.jdbc.useFetchSizeWithLongColumn=true
JNI Option: -Dsun.locale.formatasdefault=true
JNI Option: -Dorg.netbeans.CLIHandler.server=false
JNI Option: -Dide.AssertTracingDisabled=true
JNI Option: -Doracle.ide.util.AddinPolicyUtils.OVERRIDE_FLAG=true
JNI Option: -Djava.util.logging.config.file=logging.conf
JNI Option: -Dsqldev.debug=false
JNI Option: -Dsqldev.onsd=true
JNI Option: -Dide.startingArg0=C:\oracle\sqldeveloper\sqldeveloper\bin\sqldeveloper64.exe
JNI Option: -Dide.startingArg1=-verbose
JNI Option: -Dide.launcherProcessId=1256
JNI Option: -Dide.config_pathname=C:\oracle\sqldeveloper\sqldeveloper\bin\sqldeveloper.conf
JNI Option: -Dide.startingcwd=C:\oracle\sqldeveloper\sqldeveloper\bin
JNI Option: -Duser.conf=C:\Users\xcc\AppData\Roaming\sqldeveloper\4.1.3\product.conf
JNI Option: -Dtool.user.conf=C:\Users\xcc\AppData\Roaming\sqldeveloper\4.1.3\sqldeveloper.conf
JNI Option: -Dide.shell.enableFileTypeAssociation=C:\oracle\sqldeveloper\sqldeveloper\bin\sqldeveloper64.exe
JNI Option: -Dide.pref.dir.base=C:\Users\xcc\AppData\Roaming
JNI Option: -Dide.work.dir.base=C:\Users\xcc\Documents
JNI Option: -Dsun.java.command=oracle.ide.osgi.boot.OracleIdeLauncher
JNI Option: -Djava.class.path=C:\oracle\sqldeveloper\ide\lib\ide-boot.jar;C:\oracle\sqldeveloper\netbeans\platform\lib\boot.jar;C:\oracle\sqldeveloper\netbeans\platform\lib\org-openide-util-ui.jar;C:\oracle\sqldeveloper\netbeans\platform\lib\org-openide-util.jar;C:\oracle\sqldeveloper\netbeans\platform\lib\org-openide-util-lookup.jar;C:\oracle\sqldeveloper\netbeans\platform\lib\org-openide-modules.jar;C:\oracle\sqldeveloper\ide\lib\fcpboot.jar;C:\oracle\sqldeveloper\ide\lib\xml-factory.jar;C:\oracle\sqldeveloper\ide\lib\woodstox-core-asl-4.2.0.jar;C:\oracle\sqldeveloper\ide\lib\stax2-api-3.1.1.jar;C:\oracle\sqldeveloper\sqldeveloper\lib\oracle.sqldeveloper.homesupport.jar
JVM path is c:\Program Files\Java\jdk1.8.0_91\jre\bin\server\jvm.dll
LOAD TIME : 300UsersCache.fillIn() time = 29 ret==null?: true