Firebase values may produce Java.land.NullPointerException when comparing
49
What is a NullPointerException, and how do I fix it?
123797
Not equal  != operator on NULL
97224
Implementing the equals method in java
13711
java.lang.NullPointerException at org.glassfish.hk2.classmodel.reflect.impl.TypesImpl.getType
152733
How to simplify a null-safe compareTo() implementation?
144658
System.NullPointerException: Attempt to de-reference a null object ,sravn
64200
Can Java's NullPointerException be changed to report on which variable was null?
39310
How do you compare two version Strings in Java?
89052
When overriding equals in Java, why does it not work to use a parameter other than Object?
114604
How to compare two java objects
89714
What is the difference between Nullable.HasValue or Nullable != null?
64332
avoiding null reference exceptions
78156
String.equals() with multiple conditions (and one action on result)
87728
ArgumentNullException or NullReferenceException from extension method?
43446
JSONException: Value of type java.lang.String cannot be converted to JSONObject
120808
Why AbstractCollection does not implement equals()?
58054
When is it OK to catch NullPointerException?