Code macro Plugin 2.2.4 raises "Unable to scan for host components in plugin classes" exception

I tried to upgrade the Code Macro plugin from 2.1.4 to 2.2.4 on our Confluence 5.4.4 instance but that failed in the UPM (no error output in the front end). Retried after upgrading Confluence to 5.5.7 but it still fails.

Following is the log output:

{preformat}
2016-03-26 01:06:56,151 ERROR [localhost-startStop-1] [atlassian.plugin.loaders.ScanningPluginLoader] deployPluginFromUnit Unable to deploy plugin 'com.atlassian.confluence.ext.newcode-macro-plugin' from 'Unit: C:\Program Files\Atlassian\Confluence\Home\plugins-cache\1458946862000plugin.7751525215183161508.newcode-macro-plugin-2.2.4.jar (1458946862000)'.
2016-03-26 01:06:56,151 ERROR [localhost-startStop-1] [atlassian.plugin.loaders.ScanningPluginLoader] deployPluginFromUnit Because of the following exception:
com.atlassian.plugin.PluginParseException: Unable to scan for host components in plugin classes
at com.atlassian.plugin.osgi.factory.transform.stage.HostComponentSpringStage.execute(HostComponentSpringStage.java:62)
at com.atlassian.plugin.osgi.factory.transform.DefaultPluginTransformer.transform(DefaultPluginTransformer.java:146)
at com.atlassian.plugin.osgi.factory.OsgiPluginFactory.createOsgiPluginJar(OsgiPluginFactory.java:301)
at com.atlassian.plugin.osgi.factory.OsgiPluginFactory.create(OsgiPluginFactory.java:224)
at com.atlassian.plugin.loaders.ScanningPluginLoader.deployPluginFromUnit(ScanningPluginLoader.java:155)
at com.atlassian.plugin.loaders.ScanningPluginLoader.loadAllPlugins(ScanningPluginLoader.java:89)
at com.atlassian.plugin.loaders.ForwardingPluginLoader.loadAllPlugins(ForwardingPluginLoader.java:36)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:307)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:182)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:106)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
at com.sun.proxy.$Proxy12.loadAllPlugins(Unknown Source)
at com.atlassian.plugin.loaders.PermissionCheckingPluginLoader.loadAllPlugins(PermissionCheckingPluginLoader.java:24)
at com.atlassian.plugin.manager.DefaultPluginManager.init(DefaultPluginManager.java:250)
at com.atlassian.confluence.plugin.ConfluencePluginManager.init(ConfluencePluginManager.java:123)
at com.atlassian.confluence.plugin.PluginFrameworkContextListener.contextInitialized(PluginFrameworkContextListener.java:54)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4939)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5434)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.io.IOException: Error parsing class file
at com.atlassian.plugin.osgi.util.ClassBinaryScanner.scanClassBinary(ClassBinaryScanner.java:66)
at com.atlassian.plugin.osgi.factory.transform.stage.HostComponentSpringStage.findUsedHostComponents(HostComponentSpringStage.java:194)
at com.atlassian.plugin.osgi.factory.transform.stage.HostComponentSpringStage.execute(HostComponentSpringStage.java:58)
... 30 more
Caused by: java.lang.ArrayIndexOutOfBoundsException: 18
at aQute.lib.osgi.Clazz.parseClassFile(Clazz.java:448)
at aQute.lib.osgi.Clazz.parseClassFile(Clazz.java:369)
at aQute.lib.osgi.Clazz.parseClassFileWithCollector(Clazz.java:359)
at com.atlassian.plugin.osgi.util.ClassBinaryScanner.scanClassBinary(ClassBinaryScanner.java:38)
... 32 more{preformat}

Code macro Plugin 2.1.4 works fine with Confluence 5.4.4 as well as 5.5.7 here.