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Eclipse + Maven + AppEngine: Invalid classpath publish/export dependency

While working with Eclipse and Google Plugin for Eclipse the Maven Integration Plugin I ran into the problem that the dependency on the JDO API library jdo2-api-2.3-ea.jar appears in the App Engine SDK and in the Maven dependencies imported from another project. The Eclipse Classpath Dependency Validator showed the following error message:

Invalid classpath publish/export dependency /local/eclipse/galileo/plugins/com.google.appengine.eclipse.sdkbundle_1.2.2.v200907291526/appengine-java-sdk-1.2.2/lib/user/orm/jdo2-api-2.3-ea.jar. The project contains another dependency with the same archive name.

The solution for this problem was using the notion of explicit dependency exclusion of Maven 2.x in the pom.xml.

Tags: Eclipse, GWT, Maven

XPP3 pull-parser causing an ArrayIndexOutOfBoundsException: Google GWT with Eclipse, Maven and Hibernate

Today I lost almost two hours of productive work because I had problems compiling a simple Google GWT application. For software development I use Eclipse 3.4 (Ganymede) with the Maven Integration plugin. In case of GWT I also use the Cypal Studio.

My GWT application makes RPCs to a server backed by Hibernate. Including Hibernate (org.hibernate:hibernate-core-3.3.1.GA from the JBoss repository) into the classpath via Maven also includes XPP3 and the pull-parser-2 libraries. Then for some reason the Google GWT compiler uses the pull-parser-2 to parse the XML of the inherited modules.

The module com.google.gwt.user.User includes the module com.google.gwt.i18n.I18N which causes an ArrayIndexOutOfBoundsException:

[ERROR] Line 29: Unexpected exception while processing element 'inherits'
java.lang.ArrayIndexOutOfBoundsException: null
    at java.lang.System.arraycopy(Native Method)
    at org.gjt.xpp.impl.tokenizer.Tokenizer.next(Tokenizer.java:1274)
    at org.gjt.xpp.impl.pullparser.PullParser.next(PullParser.java:392)
    at org.gjt.xpp.sax2.Driver.parseSubTree(Driver.java:415)
    at org.gjt.xpp.sax2.Driver.parse(Driver.java:310)
    at com.google.gwt.dev.util.xml.ReflectiveParser$Impl.parse(ReflectiveParser.java:310)

This seems to be a bug in the pull-parser-2. Excluding the pull-parser from the hibernate-core dependency removes it from the class path, but the GWT compiler continues using it for parsing its XML modules. The solution was to include the pull-parser-2.1.10 in the Java Build Path of Eclipse and put it to the first position in the build class path order in Eclipse.

Tags: Ajax, Eclipse, GWT, Hibernate, Maven, XML Parser