digester.addObjectCreate( "!*/b", BetaBean.class );
digester.addObjectCreate( "!*/a", AlphaBean.class );
digester.addObjectCreate( "root", ArrayList.class );
digester.addSetProperties( "!*" );
digester.addSetTop( "!*/b/?", "setParent" );
digester.addSetTop( "!*/a/?", "setParent" );
digester.addSetRoot( "!*/a", "add" );
digester.addSetRoot( "!*/b", "add" );
ArrayList<?> root = digester.parse( getInputStream( "Test4.xml" ) );
assertEquals( "Wrong array size", 5, root.size() );