Cannot Invoke Method isAssignableFrom() on Null Object


Grails error message in Cinnamon Entitylib


Grails 1.3.1

Java 6

Java Domain classes with JPA 1

Project: Cinnamon / Entitylib and AdminTool (Dandelion):

Problem description

A normal call to load a GORM object (Java Domain class) fails with a strange error message:

java.lang.NullPointerException: Cannot invoke method isAssignableFrom() on null object
at java_lang_Class$ Source)
at eu.hornerproject.dandelion.IndexTypeController$_closure5.doCall(IndexTypeController.groovy:75)
at eu.hornerproject.dandelion.IndexTypeController$_closure5.doCall(IndexTypeController.groovy

The code in question:

    def indexTypeInstance = IndexType.get( contains a valid id.

The IndexType class is mapped.

Note that there is absolutely no hint as to what causes this problem - java.lang.Class is called from an unknown source, and stepping through to it by debugger is a quite impractical, because Grails / Groovy does so many things during the IndexType.get() step that you will probably die of old age before you find the problem.

(Probable) Cause & Solution

The IndexType class was missing getters and setters, and I guess the later ones are being used by GORM to set the indexerClass- and vaProvider-class fields.

[DM_API_E_EXIST] Error: Document/object Specified by Does Not Exist.


An obscure error in Documentum 5.3

Error message:

[DM_API_E_EXIST]error:  "Document/object specified by  does not exist."

System: Documentum 5.3 SP5 / Oracle 10 / Windows Server 2003

Code using dfc.jar:

IDfSysObject report = ...;
if (report == null) {
    report = (IDfSysObject) session.newObject("dm_document");
    report.setObjectName("my log");;;

Solution / Explanation:

The code called session.disconnect() before session.newObject(…).

DCTM 5.3 does not return a proper error message like “session is invalid or disconnected”

LifecycleException: Protocol Handler Initialization Failed: Address Already in Use

LifecycleException: Protocol Handler Initialization Failed: Address Already in Use:8080



Invisible programm listening on port 8080

System: Ubuntu 9.10 / Grails 1.2.1 / Java 6

When: while starting a grails application, the following error occured: Error Message

LifecycleException:  Protocol handler initialization failed: Address already in use<null>:8080
at org.grails.tomcat.TomcatServer.start(TomcatServer.groovy:135)
at grails.web.container.EmbeddableServer$ Source)
at _GrailsRun_groovy$_run_closure5_closure12.doCall(_GrailsRun_groovy:158)
at _GrailsRun_groovy$_run_closure5_closure12.doCall(_GrailsRun_groovy)
at _GrailsSettings_groovy$_run_closure10.doCall(_GrailsSettings_groovy:287)
at _GrailsSettings_groovy$
at _GrailsRun_groovy$_run_closure5.doCall(_GrailsRun_groovy:149)
at _GrailsRun_groovy$
at _GrailsRun_groovy.runInline(_GrailsRun_groovy:115)
at _GrailsRun_groovy.this$4$runInline(_GrailsRun_groovy)
at _GrailsRun_groovy$_run_closure1.doCall(_GrailsRun_groovy:59)
at RunApp$_run_closure1.doCall(RunApp.groovy:33)
at gant.Gant$_dispatch_closure4.doCall(Gant.groovy:324)
at gant.Gant$_dispatch_closure6.doCall(Gant.groovy:334)
at gant.Gant$_dispatch_closure6.doCall(Gant.groovy)
at gant.Gant.withBuildListeners(Gant.groovy:344)
at gant.Gant.this$2$withBuildListeners(Gant.groovy)
at gant.Gant$this$2$withBuildListeners.callCurrent(Unknown Source)
at gant.Gant.dispatch(Gant.groovy:334)
at gant.Gant.this$2$dispatch(Gant.groovy)
at gant.Gant.invokeMethod(Gant.groovy)
at gant.Gant.processTargets(Gant.groovy:495)
at gant.Gant.processTargets(Gant.groovy:480)
Server failed to start: LifecycleException:  Protocol handler initialization failed: Address already in use<null>:8080

$ netstat -tupl

(Es konnten nicht alle Prozesse identifiziert werden; Informationen über
nicht-eigene Processe werden nicht angezeigt; Root kann sie anzeigen.)
Aktive Internetverbindungen (Nur Server)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 localhost:7634          *:*                     LISTEN      -              
tcp        0      0 *:ssh                   *:*                     LISTEN      -              
tcp        0      0 localhost:ipp           *:*                     LISTEN      -              
tcp        0      0 localhost:mysql         *:*                     LISTEN      -              
tcp6       0      0 [::]:ssh                [::]:*                  LISTEN      -              
tcp6       0      0 localhost:ipp           [::]:*                  LISTEN      -              
tcp6       0      0 [::]:http-alt           [::]:*                  LISTEN      -              


Executing netstat as normal user hides the programm which is using port 8080 (in this case, an unexpected tomcat instance).


  1. shutdown tomcat6 running on port 8080

    sudo /etc/init.d/tomcat6 stop

  2. use netstat as root

    sudo netstat -tupl tcp6 0 0 [::]:http-alt [::]:* LISTEN 1972/jsvc

[originally posted in 2010]

Fail to Import Ssl Certificate



A client bought a new Certificate and needed to have it installed.


  1. make sure that the certificate is not borked: there should be a newline between —-BEGIN CERTIFICATE— and the data.
  2. If necessary, convert to DER format:

    openssl x509 -in myCert -out myCert.der -outform DER

  3. Import intermediate certs with different alias than the one used for your own cert:

    keytool -keystore theKeyStore -alias thawte_intermediate -import -file thawte_int.der -trustcacerts

  4. Import your new cert

    keytool -keystore theKeyStore -import -file _new_cert.der -trustcacerts




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