NullPointerException: 'void android.widget.Button.setText(java.lang.CharSequence)' on a null object reference

Question

Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setText(java.lang.CharSequence)' on a null object reference at com.example.mentalhealth.diary.onCreate(diary.java:49)

Answer 1

In your diary.java, @line no:49, in the onCreate() method, it appears that you are using an object which is not instantiated.

Calling a method on that object (which is just declared , but not instantiated using new classname() syntax).

if your file is shared , at least the 49th line of your sourcecode, it would be easy to correctly mention .