Blankj/AndroidUtilCode · error · UnsupportedOperationException

u can't instantiate me...

Error message

u can't instantiate me...

What it means

ZipUtils is a final static-only utility for zip/unzip operations. Its private constructor throws UnsupportedOperationException to prevent instantiation. All public methods (zipFiles, unzipFile, etc.) are static.

Source

Thrown at lib/utilcode/src/main/java/com/blankj/utilcode/util/ZipUtils.java:34

import java.util.List;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
import java.util.zip.ZipOutputStream;

/**
 * <pre>
 *     author: Blankj
 *     blog  : http://blankj.com
 *     time  : 2016/08/27
 *     desc  : utils about zip
 * </pre>
 */
public final class ZipUtils {

    private static final int BUFFER_LEN = 8192;

    private ZipUtils() {
        throw new UnsupportedOperationException("u can't instantiate me...");
    }

    /**
     * Zip the files.
     *
     * @param srcFiles    The source of files.
     * @param zipFilePath The path of ZIP file.
     * @return {@code true}: success<br>{@code false}: fail
     * @throws IOException if an I/O error has occurred
     */
    public static boolean zipFiles(final Collection<String> srcFiles,
                                   final String zipFilePath)
            throws IOException {
        return zipFiles(srcFiles, zipFilePath, null);
    }

    /**
     * Zip the files.

View on GitHub (pinned to 7b4caf9e54)

Solutions

  1. Use static methods: ZipUtils.zipFiles(files, path) instead of constructing the class.
  2. Provide a Gson InstanceCreator / Jackson mixin returning a sentinel so the constructor is not invoked.
  3. Use Mockito.mockStatic for mocking rather than constructing ZipUtils.
  4. Keep the class final with a private constructor.

Example fix

// before
ZipUtils zu = new ZipUtils();

// after
ZipUtils.zipFiles(fileList, "/sdcard/out.zip");
Defensive patterns

Strategy: validation

Validate before calling

if (Modifier.isFinal(ZipUtils.class.getModifiers())) {
  throw new IllegalStateException("ZipUtils is static-only.");
}

Prevention

When it happens

Trigger: Reflective instantiation via ZipUtils.class.getDeclaredConstructor().setAccessible(true).newInstance(), or transitively through Gson/Jackson deserialization, Mockito/PowerMock, Kotlin reflection, or a DI classpath scan.

Common situations: Serialization frameworks binding a field to ZipUtils; mock frameworks in tests; coverage probes; accidental `new ZipUtils()` after weakening modifiers.

Related errors

AI-assisted analysis of Blankj/AndroidUtilCode@7b4caf9e54 (2026-08-14). Data as JSON: /api/errors/6e77e1072b8b7030. Report an issue: GitHub.