### Question:
AppConfiguration { public String getString(final String propertyName) { if(this.javaSystemConfig.containsKey(propertyName)) { return this.javaSystemConfig.getString(propertyName); } List<String> propertiesToAttempt = getOrderedPropertyList(propertyName); for (String propertyToAttempt : propertiesToAttempt) { if (this.serviceConfig.containsKey(propertyToAttempt)) { return this.serviceConfig.getString(propertyToAttempt); } } log.warn("No value found for property named \"" + propertyName + "\""); return null; } private  AppConfiguration(); boolean isCronConnector(); void initialize(final boolean isRunningCmdLine, final String connectorType, final String projectName); void clear(); boolean hasProperty(final String propertyName); String getString(final String propertyName); String getString(final String propertyName, final String defaultValue); String[] getList(final String propertyName); String[] getList(final String propertyName, final String[] defaultValue); long getLong(final String propertyName); long getLong(final String propertyName, final long defaultValue); int getInt(final String propertyName); int getInt(final String propertyName, final int defaultValue); float getFloat(final String propertyName); float getFloat(final String propertyName, final float defaultValue); double getDouble(final String propertyName); double getDouble(final String propertyName, final double defaultValue); boolean getBoolean(final String propertyName); boolean getBoolean(final String propertyName, final boolean defaultValue); AWSCredentialsProvider getCredentialsProvider(); boolean isRunningCmdLine(); String getConnectorType(); String getProjectName(); HealthCheckController getHealthCheckController(); void setHealthCheckController(final HealthCheckController healthCheckController); static final AppConfiguration INSTANCE; }### Answer:
@Test public void testOverrides() { Assert.assertEquals("value1", AppConfiguration.INSTANCE.getString("property_a")); Assert.assertEquals("value2", AppConfiguration.INSTANCE.getString("property_b")); Assert.assertEquals("value3", AppConfiguration.INSTANCE.getString("property_c")); Assert.assertEquals("value4", AppConfiguration.INSTANCE.getString("property_d")); Assert.assertEquals("value5", AppConfiguration.INSTANCE.getString("property_e")); Assert.assertEquals("value6", AppConfiguration.INSTANCE.getString("property_f")); }