gwt-entities-canvas org.eclipse.jdt.core.javabuilder com.google.gdt.eclipse.core.webAppProjectValidator com.google.gwt.eclipse.core.gwtProjectValidator org.eclipse.m2e.core.maven2Builder org.eclipse.jdt.core.javanature com.google.gwt.eclipse.core.gwtNature org.eclipse.m2e.core.maven2Nature