[GROOVY-927] IncompatibleClassChangeError when implementing a class instead of extending it

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.0-JSR-2
• Fix Version/s: 1.0-JSR-3
• Component/s: class generator, parser-antlr2
• Assignee: Jochen Theodorou
• Reporter: Guillaume Sauthier
• Created: 27/Jun/05 08:39
• Updated: 06/Jul/05 08:45
• Resolved: 06/Jul/05 08:45

Description

Inside a script, I was writing a new Builder class, by extending BuilderSupport, but I mistakenly implemented the base class, instead of extending it, and I got this error:

IncompatibleClassChangeError: Implementing class

The solution was to replace "implements" with "extends" but the error was misleading and not obious.

Here is a script which shows the problem in action:

println "error"

class GrammarBuilder implements BuilderSupport {
def createNode(name, Map map, closure) {}
void setParent(name, closure) {}
def createNode(name, Map map) {}
Object createNode(name, closure) {}
Object createNode(name) {}
}