The Bugs which i have experienced and analysed

1. created a table without the primary key name as _id
 java.lang.IllegalArgumentException: column '_id' does not exist
        at android.database.AbstractCursor.getColumnIndexOrThrow(Abstr

2. changed to _id but table not replaced
android.database.sqlite.SQLiteException: no such column: _id

3. Used button first and Edittext next
caused by java.lang.classcastexception android.widget.edittext
 <requestFocus />

4. Should not close the database at needed times
java.lang.IllegalStateException: attempt to acquire a reference on a close SQLiteClosable

5. I used two buttons with onclicklistener
E/AndroidRuntime( 8908): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.sampleapp.application/com.sampleapp.application.LoginActivity}: java.lang.ClassCastException: android.widget.EditText

6. I tried to display Toast with integer value
android.content.res.Resources$NotFoundException: String resource ID #0x2f
        at android.content.res.Resources.getText(Resources.java:200)
        at android.widget.Toast.makeText(Toast.java:258)

7. Toast is not working, rather this msg displayed in log
I/NotificationService(   51): enqueueToast pkg=com.sampleapp.application callback=android.app.ITransientNotification$Stub$Proxy@44d30338 duration=0

8. java.net.SocketException: Permission denied (maybe missing INTERNET permission)
    add the permission in Android.manifest file "android.permission.INTERNET"

9.  Uncaught handler: thread main exiting due to uncaught exception
 android.content.ActivityNotFoundException: No Activity found to handle Intent { act=android.intent.action.CALL dat=9977666612 }

10. W/PhoneUtils(  120): Exception from phone.dial()
W/PhoneUtils(  120): com.android.internal.telephony.CallStateException: cannot dial in current state

11.  com.android.internal.telephony.CallStateException: cannot dial in current state
                  This error comes while we dial mobile numbers in a sequence.