Blankj/AndroidUtilCode · error · UnsupportedOperationException

u can't instantiate me...

Error message

u can't instantiate me...

What it means

MetaDataUtils is a final utility class providing static methods for reading Android manifest meta-data values (getMetaDataInApp, getMetaDataInActivity). Its private constructor throws UnsupportedOperationException to enforce static-only access.

Source

Thrown at lib/utilcode/src/main/java/com/blankj/utilcode/util/MetaDataUtils.java:24

import android.content.ComponentName;
import android.content.pm.ActivityInfo;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
import android.content.pm.ServiceInfo;
import androidx.annotation.NonNull;

/**
 * <pre>
 *     author: Blankj
 *     blog  : http://blankj.com
 *     time  : 2018/05/15
 *     desc  : utils about meta-data
 * </pre>
 */
public final class MetaDataUtils {

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

    /**
     * Return the value of meta-data in application.
     *
     * @param key The key of meta-data.
     * @return the value of meta-data in application
     */
    public static String getMetaDataInApp(@NonNull final String key) {
        String value = "";
        PackageManager pm = Utils.getApp().getPackageManager();
        String packageName = Utils.getApp().getPackageName();
        try {
            ApplicationInfo ai = pm.getApplicationInfo(packageName, PackageManager.GET_META_DATA);
            value = String.valueOf(ai.metaData.get(key));
        } catch (PackageManager.NameNotFoundException e) {
            e.printStackTrace();
        }

View on GitHub (pinned to 7b4caf9e54)

Solutions

  1. Use static methods: MetaDataUtils.getMetaDataInApp(key). Never call new MetaDataUtils().
  2. Exclude utility classes from DI scanning and serialization configs.
  3. Mock static methods with mockito-inline for testing.

Example fix

// before
MetaDataUtils mdu = new MetaDataUtils();
String val = mdu.getMetaDataInApp("api_key");

// after
String val = MetaDataUtils.getMetaDataInApp("api_key");
Defensive patterns

Strategy: type-guard

Validate before calling

// MetaDataUtils is static-only
String value = MetaDataUtils.getMetaDataInApp("com.google.android.gms.version");

Type guard

static boolean isStaticUtility(Class<?> c) {
    return Modifier.isFinal(c.getModifiers()) && c.getSimpleName().endsWith("Utils");
}

Try / catch

try {
    MetaDataUtils.class.getDeclaredConstructor().setAccessible(true);
    MetaDataUtils.class.getDeclaredConstructor().newInstance();
} catch (UnsupportedOperationException e) {
    // Use static methods
}

Prevention

When it happens

Trigger: Direct or reflective instantiation by DI frameworks, mocking libraries, serialization frameworks, or manual reflection calls via Constructor.newInstance().

Common situations: Component scanning traverses the utility package; a test runner instantiates all classes in a package for coverage; a serialization library targets the class for deserialization.

Related errors

AI-assisted analysis of Blankj/AndroidUtilCode@7b4caf9e54 (2026-08-14). Data as JSON: /api/errors/3d3c95e5f3c57483. Report an issue: GitHub.