### Question:
CompressionPluginType extends BasePluginType implements PluginTypeInterface { public static CompressionPluginType getInstance() { if ( pluginType == null ) { pluginType = new CompressionPluginType(); } return pluginType; } private  CompressionPluginType(); static CompressionPluginType getInstance(); String[] getNaturalCategoriesOrder();  }### Answer:
@Test public void testGetInstance() { CompressionPluginType instance = CompressionPluginType.getInstance(); CompressionPluginType instance2 = CompressionPluginType.getInstance(); assertTrue( instance == instance2 ); assertNotNull( instance ); CompressionPluginType.pluginType = null; CompressionPluginType instance3 = CompressionPluginType.getInstance(); assertFalse( instance == instance3 ); }