- **Type safety** - Extensive use of generics and null-safe operations throughout the API
- **Resource management** - Proper handling of resources with utilities like `CloseableUtil` and `DisposableUtil`

### Key Architectural Patterns
- **Factory Pattern** - `BeanDescFactory` for creating bean descriptors, `ParameterizedClassDescFactory` for generic type handling

import java.util.Map;

import org.codelibs.core.exception.ClIllegalArgumentException;
import org.codelibs.core.message.MessageFormatter;
import org.codelibs.core.misc.DisposableUtil;

/**
 * Logger interface.
 *
 * @author higa
 */
public class Logger {

    /**
     * Log output levels.
     */
    public enum LogLevel {
        /** Debug */
        DEBUG,