new PropertiesFileConfiguration( "test", new File( "test-res/SystemConfig/system/test.properties" ) );
systemConfig.registerConfiguration( c );
IConfiguration configuration = systemConfig.getConfiguration( "test" );
Properties props = configuration.getProperties();
props.setProperty( "someProperty", "new value" );
configuration.update( props );
FileSystemXmlApplicationContext context =
new FileSystemXmlApplicationContext( "test-res/SystemConfig/system/testPropertyPlaceholders.spring.xml" );
context.refresh();