Error123: Attempt to invoke virtual method 'boolean java.lang.Object.equals(java.lang.Object)' on a null object reference
49
What is a NullPointerException, and how do I fix it?
152733
How to simplify a null-safe compareTo() implementation?
5640
How to check a string against null in java?
124471
Comparing nullable column values using "IS NULL" versus "= NULL"
33981
How to override equals method in Java
110721
Nullable types and the ternary operator: why is `? 10 : null` forbidden?
148619
Is there a reason not to use  (null safe equals operator) in mysql instead of =?
10581
Avoiding NullPointerException in Java
39781
Why does the is operator return false when given null?
140738
Does setting Java objects to null do anything anymore?
65377
Trouble over riding and using equals method in java
155686
What is a reason of placing boolean or null before comparison operator?
665
Which equals operator (== vs ===) should be used in JavaScript comparisons?
73430
C# .Equals(), .ReferenceEquals() and == operator
5608
Overriding the java equals() method - not working?
85964
Android: ClassNotFoundException when passing serializable object to Activity
38241
How do I check for nulls in an '==' operator overload without infinite recursion?