### Question:
NetShellConfiguration extends PersistentObject { public static NetShellConfiguration getInstance() { if (instance == null) { try { NetShellConfiguration tmp = NetShellConfiguration.loadConfiguration(); if (instance == null) { instance = tmp; } } catch (Exception e) { if (instance == null) { instance = new NetShellConfiguration(true); instance.global = new GlobalConfiguration(); } } } return instance; } NetShellConfiguration(boolean canSet);  NetShellConfiguration(); static NetShellConfiguration getInstance(); GlobalConfiguration getGlobal(); final synchronized void setGlobal(GlobalConfiguration global); void save(File file); @JsonIgnore
    static String DEFAULT_FILENAME; }### Answer:
@Test public void testGetInstance() throws Exception { NetShellConfiguration conf = NetShellConfiguration.getInstance(); }