180     abstract static class RecyclableSingleton<T> {
 181         final T get() {
 182             return AppContext.getSoftReferenceValue(this, () -> getInstance());
 183         }
 184 
 185         void reset() {
 186             AppContext.getAppContext().remove(this);
 187         }
 188 
 189         abstract T getInstance();
 190     }
 191 
 192     static class RecyclableSingletonFromDefaultConstructor<T> extends RecyclableSingleton<T> {
 193         private final Class<T> clazz;
 194 
 195         RecyclableSingletonFromDefaultConstructor(final Class<T> clazz) {
 196             this.clazz = clazz;
 197         }
 198 
 199         @Override

 200         T getInstance() {
 201             try {
 202                 ReflectUtil.checkPackageAccess(clazz);
 203                 return clazz.newInstance();
 204             } catch (InstantiationException | IllegalAccessException ignored) {
 205             }
 206             return null;
 207         }
 208     }
 209 
 210     abstract static class LazyKeyedSingleton<K, V> {
 211         private Map<K, V> refs;
 212 
 213         V get(final K key) {
 214             if (refs == null) refs = new HashMap<>();
 215 
 216             final V cachedValue = refs.get(key);
 217             if (cachedValue != null) return cachedValue;
 218 
 219             final V value = getInstance(key);

 180     abstract static class RecyclableSingleton<T> {
 181         final T get() {
 182             return AppContext.getSoftReferenceValue(this, () -> getInstance());
 183         }
 184 
 185         void reset() {
 186             AppContext.getAppContext().remove(this);
 187         }
 188 
 189         abstract T getInstance();
 190     }
 191 
 192     static class RecyclableSingletonFromDefaultConstructor<T> extends RecyclableSingleton<T> {
 193         private final Class<T> clazz;
 194 
 195         RecyclableSingletonFromDefaultConstructor(final Class<T> clazz) {
 196             this.clazz = clazz;
 197         }
 198 
 199         @Override
 200         @SuppressWarnings("deprecation") // Class.newInstance
 201         T getInstance() {
 202             try {
 203                 ReflectUtil.checkPackageAccess(clazz);
 204                 return clazz.newInstance();
 205             } catch (InstantiationException | IllegalAccessException ignored) {
 206             }
 207             return null;
 208         }
 209     }
 210 
 211     abstract static class LazyKeyedSingleton<K, V> {
 212         private Map<K, V> refs;
 213 
 214         V get(final K key) {
 215             if (refs == null) refs = new HashMap<>();
 216 
 217             final V cachedValue = refs.get(key);
 218             if (cachedValue != null) return cachedValue;
 219 
 220             final V value = getInstance(key);