How to Resolve Java.Lang.RuntimeException: Unable to Instantiate Activity ComponentInfo

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Mehvish Ashiq Feb 02, 2024
Java Java Error
How to Resolve Java.Lang.RuntimeException: Unable to Instantiate Activity ComponentInfo

Today, we will learn about another runtime exception that says Unable to instantiate activity ComponentInfo.

We will explore different possible reasons that result in java.lang.RuntimeException: Unable to instantiate activity ComponentInfo. Finally, we will have a solution to eradicate it.

Resolve the java.lang.RuntimeException: Unable to instantiate activity ComponentInfo Error

Example Code for Error Demonstration (MainActivity.java file):

public class MainActivity extends Activity {
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
  }
  // write your remaining code here
}

Example Code (AndroidManifest.xml file):

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    package="com.example.app">

    <application
        android:allowBackup="true"
        android:dataExtractionRules="@xml/data_extraction_rules"
        android:fullBackupContent="@xml/backup_rules"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.App"
        tools:targetApi="31">

        <activity
            android:name="MainActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

    </application>

</manifest>

When we try to run this while launching an application in the android emulator, we get the error saying java.lang.RuntimeException: Unable to instantiate activity ComponentInfo.

There are a few possible causes that we must consider to resolve this. All of them are listed below.

  • Make sure that your Activity is added to the AndroidManifest.xml file. Why is it necessary?

    It is because whenever we want to make a new Activity, we must register in our AndroidManifest.xml file. Also, verify all the access modifiers.

  • We also get this error when we try to view before onCreate(), which is incorrect and results in an error stating unable to instantiate activity component info error.

  • Another reason for getting java.lang.RuntimeException: Unable to instantiate activity ComponentInfo is that we have added our Activity in AndroidManifest.xml, which is declared as abstract. In other words, we can say that the Activity we are trying to access is declared abstract.

  • Make sure that we are not missing a preceding dot before an activity path (this thing is causing an error in the example code given above).

  • We also have to face this error if we did not declare our MainActivity.java file as public. Also, check if your file is in the right package or not.

Now, we know all the possible reasons. How can we fix it?

See the following solution.

Example Code for Solution (MainActivity.java file):

public class MainActivity extends Activity {
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
  }
  // write your remaining code here
}

Example Code (AndroidManifest.xml file):

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    package="com.example.app">

    <application
        android:allowBackup="true"
        android:dataExtractionRules="@xml/data_extraction_rules"
        android:fullBackupContent="@xml/backup_rules"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.App"
        tools:targetApi="31">

        <activity
            android:name=".MainActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

    </application>

</manifest>

We have added a preceding dot before an activity path. We also confirm that our MainActivity.java file is declared as public, and we are not trying to access an Activity declared as abstract.

Be careful of all the points given as causes because those points are actual solutions if we consider them.

Author: Mehvish Ashiq
Mehvish Ashiq avatar Mehvish Ashiq avatar

Mehvish Ashiq is a former Java Programmer and a Data Science enthusiast who leverages her expertise to help others to learn and grow by creating interesting, useful, and reader-friendly content in Computer Programming, Data Science, and Technology.

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