### Question:
ConfigFactory { @Nonnull public static IConfig getDefaultConfig () { return DEFAULT_INSTANCE; } private  ConfigFactory(); @Nonnull static MultiConfigurationValueProvider createValueProviderSystemOnly(); @Nonnull static ReadableResourceProviderChain createDefaultResourceProviderChain(); @Nonnull static MultiConfigurationValueProvider createDefaultValueProvider(); @Nonnull static IConfig getSystemConfig(); @Nonnull static IConfig getDefaultConfig(); static final int PRIVATE_APPLICATION_JSON_PRIORITY; static final int PRIVATE_APPLICATION_PROPERTIES_PRIORITY; static final int APPLICATION_JSON_PRIORITY; static final int APPLICATION_PROPERTIES_PRIORITY; static final int REFERENCE_PROPERTIES_PRIORITY; }### Answer:
@Test public void testSystemPropertyBoolean () { assertTrue (ConfigFactory.getDefaultConfig ().getAsBoolean ("key.key2", true)); assertFalse (ConfigFactory.getDefaultConfig ().getAsBoolean ("key.key2", false)); SystemProperties.setPropertyValue ("key.key2", true); try { assertTrue (ConfigFactory.getDefaultConfig ().getAsBoolean ("key.key2")); } finally { SystemProperties.removePropertyValue ("key.key2"); } SystemProperties.setPropertyValue ("key.key2", false); try { assertFalse (ConfigFactory.getDefaultConfig ().getAsBoolean ("key.key2")); } finally { SystemProperties.removePropertyValue ("key.key2"); } SystemProperties.setPropertyValue ("key.key2", "bla"); try { assertFalse (ConfigFactory.getDefaultConfig ().getAsBoolean ("key.key2")); } finally { SystemProperties.removePropertyValue ("key.key2"); } }