Why I get ClassNotFoundException when I add plugin to Grails? - grails

Question

I used Grails 2.5.6(set by sdkman) with Java 8. When I add some plugins to dependencies, for example 'org.grails.plugins:quartz:2.0.12' or 'org.grails.plugins:grails-java8:1.2.2' I get error during starting Grails app.
Stacktrace I get:
java.lang.NoClassDefFoundError: grails/plugins/Plugin
at _PluginDependencies$_run_closure2.doCall(_PluginDependencies.groovy:48)
at org.codehaus.gant.GantMetaClass.invokeMethod(GantMetaClass.java:133)
at org.codehaus.gant.GantBinding$_initializeGantBinding_closure5_closure16_closure18.doCall(GantBinding.groovy:185)
at org.codehaus.gant.GantBinding$_initializeGantBinding_closure5_closure16_closure18.doCall(GantBinding.groovy)
at org.codehaus.gant.GantBinding.withTargetEvent(GantBinding.groovy:90)
at org.codehaus.gant.GantBinding.this$4$withTargetEvent(GantBinding.groovy)
at org.codehaus.gant.GantBinding$_initializeGantBinding_closure5_closure16.doCall(GantBinding.groovy:185)
at org.codehaus.gant.GantBinding$_initializeGantBinding_closure5_closure16.doCall(GantBinding.groovy)
at org.codehaus.gant.GantMetaClass.invokeMethod(GantMetaClass.java:133)
at _GrailsPackage$_run_closure2.doCall(_GrailsPackage.groovy:57)
at org.codehaus.gant.GantMetaClass.invokeMethod(GantMetaClass.java:133)
at org.codehaus.gant.GantBinding$_initializeGantBinding_closure5_closure16_closure18.doCall(GantBinding.groovy:185)
at org.codehaus.gant.GantBinding$_initializeGantBinding_closure5_closure16_closure18.doCall(GantBinding.groovy)
at org.codehaus.gant.GantBinding.withTargetEvent(GantBinding.groovy:90)
at org.codehaus.gant.GantBinding.this$4$withTargetEvent(GantBinding.groovy)
at org.codehaus.gant.GantBinding$_initializeGantBinding_closure5_closure16.doCall(GantBinding.groovy:185)
at org.codehaus.gant.GantBinding$_initializeGantBinding_closure5_closure16.doCall(GantBinding.groovy)
at org.codehaus.gant.GantMetaClass.processClosure(GantMetaClass.java:81)
at org.codehaus.gant.GantMetaClass.processArgument(GantMetaClass.java:95)
at org.codehaus.gant.GantMetaClass.invokeMethod(GantMetaClass.java:128)
at RunApp$_run_closure1.doCall(RunApp.groovy:28)
at org.codehaus.gant.GantMetaClass.invokeMethod(GantMetaClass.java:133)
at org.codehaus.gant.GantBinding$_initializeGantBinding_closure5_closure16_closure18.doCall(GantBinding.groovy:185)
at org.codehaus.gant.GantBinding$_initializeGantBinding_closure5_closure16_closure18.doCall(GantBinding.groovy)
at org.codehaus.gant.GantBinding.withTargetEvent(GantBinding.groovy:90)
at org.codehaus.gant.GantBinding.this$4$withTargetEvent(GantBinding.groovy)
at org.codehaus.gant.GantBinding$_initializeGantBinding_closure5_closure16.doCall(GantBinding.groovy:185)
at org.codehaus.gant.GantBinding$_initializeGantBinding_closure5_closure16.doCall(GantBinding.groovy)
at gant.Gant$_dispatch_closure5.doCall(Gant.groovy:381)
at gant.Gant$_dispatch_closure7.doCall(Gant.groovy:415)
at gant.Gant$_dispatch_closure7.doCall(Gant.groovy)
at gant.Gant.withBuildListeners(Gant.groovy:427)
at gant.Gant.this$2$withBuildListeners(Gant.groovy)
at gant.Gant.dispatch(Gant.groovy:415)
at gant.Gant.this$2$dispatch(Gant.groovy)
at gant.Gant.invokeMethod(Gant.groovy)
at gant.Gant.executeTargets(Gant.groovy:591)
at gant.Gant.executeTargets(Gant.groovy:590)
Caused by: java.lang.ClassNotFoundException: grails.plugins.Plugin
... 38 more

Answer 1

You're trying to use Grails 3+ plugins with Grails 2.x but they're not compatible. Use plugin information from https://grails.org/plugins/ and be sure to add the dependency info in the plugins block in BuildConfig.groovy, not in the dependencies block since that's for jar dependencies (Grails 2 plugins are packaged as .zip files)
It looks like the latest version of the Quartz plugin for Grails 2 is v1.0.2, so you'd add that as
plugins {
...
compile ':quartz:1.0.2'
}
There's no Java 8 plugin for Grails 2.