### Question:
OverridablePropertyPlaceholderConfigurer extends PropertyPlaceholderConfigurer { @Override public void setLocation(Resource location) { if (StringUtils.isBlank(getSystemPropertyName())) { throw new IllegalArgumentException("Missing value for 'systemPropertyName'."); } Resource locationResource; final String overrideProperty = System.getProperty(getSystemPropertyName()); if (StringUtils.isBlank(overrideProperty)) { locationResource = location; } else if (overrideProperty.startsWith(CLASSPATH)) { locationResource = new ClassPathResource(overrideProperty.substring(CLASSPATH.length())); } else { locationResource = new FileSystemResource(overrideProperty); } super.setLocation(locationResource); }  @Override void setLocation(Resource location); void setSystemPropertyName(String systemPropertyName); String getSystemPropertyName(); Map<String, String> getResolvedProps();  }### Answer:
@Test public void setLocation() { System.setProperty("portal.override.properties", "classpath:portal-test.properties"); ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("applicationContext-test.xml"); final StringBuffer testBean = (StringBuffer) context.getBean("testBean"); assertEquals("Dummy value", testBean.toString()); }