This bug was originally marked as duplicate of bug 194135, that is already resolved. This bug is still valid, so this seems to be another bug, but it might be related.

Build: NetBeans IDE 7.0 Beta 2 (Build 201102140001)
VM: Java HotSpot(TM) Client VM, 19.0-b09, Java(TM) SE Runtime Environment, 1.6.0_23-b05
OS: Windows XP

User Comments:
GUEST: I could not write code, because this message will be show up too much!
There should be a setting like 'timeout to show error' (default timeout: 3s)

GUEST: Marked text

edjon2000: Just to confirm this is definately linked to code completion in CSS files if I try to type anything in, whether it be a class declaration the exception occurs after each character is typed - for now I think I will have to temporarily switch to an alternate IDE until this problem can be rectified to enable me to complete my current project, which up until the updates earlier today, causing these errors, has been built completely on Netbeans

klauern: trying code completion on a Ruby project.

GUEST: pressing tab on code completion

kpdirection: Typing in two characters into some code.
This is UNACCEPTABLE. I know it's a dev release, but really...

GUEST: This is happening whenever it trys to auto-complete css within a style tag on a phtml file.

redic1: Typing :)

GUEST: Pressed Ctrl+Space

jsnuggs: Getting this error whenever I type in a php file that had been working fine.  I just start to type static or public and it gives this error.

GUEST: I was editing my CSS file...was typing "bor" for border when the error occured.

GUEST: I typed just the word 'null' in a php-file in the Editor.

obalyuk: trying to type and the message keeps popping up every time autocomplete should be displayed

GUEST: Nothing. Just typing.

GUEST: Any autocomplete try-out shows error.

edjon2000: Typing in a CSS class (seems to be linked to code completion in CSS files)




Stacktrace: 
java.lang.AbstractMethodError: org.netbeans.modules.ruby.RubyCodeCompleter.getApplicableTemplates(Ljavax/swing/text/Document;II)Ljava/util/Set;
   at org.netbeans.modules.csl.editor.codetemplates.GsfCodeTemplateFilter.<init>(GsfCodeTemplateFilter.java:75)
   at org.netbeans.modules.csl.editor.codetemplates.GsfCodeTemplateFilter.<init>(GsfCodeTemplateFilter.java:62)
   at org.netbeans.modules.csl.editor.codetemplates.GsfCodeTemplateFilter$Factory.createFilter(GsfCodeTemplateFilter.java:96)
   at org.netbeans.lib.editor.codetemplates.CodeTemplateManagerOperation.getTemplateFilters(CodeTemplateManagerOperation.java:230)
   at org.netbeans.lib.editor.codetemplates.CodeTemplateCompletionProvider$Query.query(CodeTemplateCompletionProvider.java:197)
   at org.netbeans.spi.editor.completion.support.AsyncCompletionTask.run(AsyncCompletionTask.java:223)