### Core Design Principles
CoreLib follows a **utility-class pattern** where most functionality is exposed through static methods:

- **Assertion-based validation** - All methods validate inputs using `AssertionUtil.assertArgumentNotNull()` and `AssertionUtil.assertArgumentNotEmpty()`
- **Exception wrapping** - Checked exceptions are consistently wrapped in runtime exceptions (e.g., `ClassNotFoundException` → `ClassNotFoundRuntimeException`)

 * governing permissions and limitations under the License.
 */
package org.codelibs.core.io;

import static org.codelibs.core.misc.AssertionUtil.assertArgumentNotEmpty;
import static org.codelibs.core.misc.AssertionUtil.assertArgumentNotNull;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.Properties;

 */
package org.codelibs.core.collection;

import static org.codelibs.core.collection.CollectionsUtil.newArrayList;
import static org.codelibs.core.misc.AssertionUtil.assertArgument;
import static org.codelibs.core.misc.AssertionUtil.assertArgumentNotNull;

import java.lang.reflect.Array;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.Arrays;
import java.util.List;

 * governing permissions and limitations under the License.
 */
package org.codelibs.core.collection;

import static org.codelibs.core.misc.AssertionUtil.assertIndex;
import static org.codelibs.core.misc.AssertionUtil.assertState;

import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.lang.reflect.Array;

import static org.codelibs.core.collection.MultiIterator.iterable;
import static org.codelibs.core.lang.StringUtil.isEmpty;
import static org.codelibs.core.lang.StringUtil.isNotEmpty;
import static org.codelibs.core.misc.AssertionUtil.assertArgumentNotNull;

import java.text.DateFormat;
import java.text.ParsePosition;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.Iterator;

 * governing permissions and limitations under the License.
 */
package org.codelibs.core.jar;

import static org.codelibs.core.log.Logger.format;
import static org.codelibs.core.misc.AssertionUtil.assertArgumentNotNull;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.JarURLConnection;
import java.net.URL;
import java.net.URLConnection;

 * either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */
package org.codelibs.core.nio;

import static org.codelibs.core.misc.AssertionUtil.assertArgumentNotNull;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.Channel;
import java.nio.channels.FileChannel;
import java.nio.channels.FileChannel.MapMode;

import static org.codelibs.core.collection.CollectionsUtil.newHashMap;
import static org.codelibs.core.lang.ClassIterator.iterable;
import static org.codelibs.core.misc.AssertionUtil.assertArgumentNotEmpty;
import static org.codelibs.core.misc.AssertionUtil.assertArgumentNotNull;

import java.sql.Time;
import java.util.List;
import java.util.Map;

import org.codelibs.core.beans.Converter;

import static org.codelibs.core.collection.CollectionsUtil.newConcurrentHashMap;
import static org.codelibs.core.collection.CollectionsUtil.newHashSet;
import static org.codelibs.core.misc.AssertionUtil.assertArgumentNotEmpty;
import static org.codelibs.core.misc.AssertionUtil.assertArgumentNotNull;

import java.io.File;
import java.net.URL;
import java.util.Iterator;
import java.util.List;
import java.util.Set;

 * governing permissions and limitations under the License.
 */
package org.codelibs.core.lang;

import static org.codelibs.core.collection.ArrayUtil.asArray;
import static org.codelibs.core.misc.AssertionUtil.assertArgumentNotNull;

import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.lang.reflect.Type;

import org.codelibs.core.exception.ClIllegalArgumentException;