This issue was originally marked as duplicate of issue 130998, that is already resolved. This issue is still valid, so this seems to be another issue, but it might be related.

Build: NetBeans IDE 6.7 (Build 200906241340)
VM: Java HotSpot(TM) 64-Bit Server VM, 14.0-b16, Java(TM) SE Runtime Environment, 1.6.0_14-b08
OS: Linux, 2.6.28-13-generic, amd64

User Comments:
fsoares: Editing a file in the java editor

GUEST: not sure

tboudreau: Copying and pasting a block of code out of one method and into another

tboudreau: Occurred after I deleted a file called ClassicAppletX, copied a file called ExtendedAppletX and refactor-pasted it as ClassicAppletX1 (note the 1), then renamed it to ClassicAppletX



Stacktrace: 
java.lang.IllegalArgumentException: TreePathHandle [/home/fs/NetBeansProjects/IOLUsers/src/test/java/pt/iol/services/mail/jerseyTest.java] was not created from /home/fs/NetBeansProjects/IOLUsers/src/test/java/pt/iol/services/mail/jerseyTest.java
mine: id=1973656894, valid=true, url=file:/home/fs/NetBeansProjects/IOLUsers/src/test/java/pt/iol/services/mail/jerseyTest.java
remote: id=1108981677, valid=true, url=file:/home/fs/NetBeansProjects/IOLUsers/src/test/java/pt/iol/services/mail/jerseyTest.java
        at org.netbeans.api.java.source.TreePathHandle$TreeDelegate.resolve(TreePathHandle.java:402)
        at org.netbeans.api.java.source.TreePathHandle.resolve(TreePathHandle.java:144)
        at org.netbeans.modules.java.hints.introduce.IntroduceHint.computeIntroduceMethod(IntroduceHint.java:482)
        at org.netbeans.modules.java.hints.introduce.IntroduceHint.computeError(IntroduceHint.java:453)
        at org.netbeans.modules.java.hints.introduce.IntroduceHint.run(IntroduceHint.java:304)
        at org.netbeans.modules.java.hints.introduce.IntroduceHint.run(IntroduceHint.java:129)