[안드로이드] java.lang.IllegalAccessException: java.lang.Class

Android Activity 실행시 AndroidManifest에 Activity 선언되어 있는데도 아래와 같은 에러가 발생함.

java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.json.example/com.json.ui.settings.Engineer}: java.lang.IllegalAccessException: java.lang.Class<com.json.mcptt.ui.settings.Engineer> is not accessible from java.lang.Class<android.app.AppComponentFactory>
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2882)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3087)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1817)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:6746)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
     Caused by: java.lang.IllegalAccessException: java.lang.Class<com.json.ui.settings.Engineer> is not accessible from java.lang.Class<android.app.AppComponentFactory>
        at java.lang.Class.newInstance(Native Method)
        at android.app.AppComponentFactory.instantiateActivity(AppComponentFactory.java:69)
        at android.support.v4.app.CoreComponentFactory.instantiateActivity(CoreComponentFactory.java:43)
        at android.app.Instrumentation.newActivity(Instrumentation.java:1216)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2870)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3087) 
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78) 
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108) 
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1817) 
        at android.os.Handler.dispatchMessage(Handler.java:106) 
        at android.os.Looper.loop(Looper.java:193) 
        at android.app.ActivityThread.main(ActivityThread.java:6746) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858) 

 

해결 방법

class Engineer extends AppCompatActivity -> public class Engineer extends AppCompatActivity

실행 Activity Class를 public으로 선언

class Engineer extends AppCompatActivity

public class Engineer extends AppCompatActivity