Boolean equals is referring to null object
49
What is a NullPointerException, and how do I fix it?
94973
Why type "int" is never equal to 'null'?
123797
Not equal  != operator on NULL
63854
How do boolean operators work in 'if' conditions?
131933
On the usage of Java equality operator
120071
Checking for a null int value from a Java ResultSet
105722
boolean properties starting with "is" does not work
90115
How can I list the nodes for which a Boolean value is FALSE or NULL?
154049
why does if("string") evaluate "string" as true but if ("string"==true) does not?
109876
In the msdn guidance on Equals override, why the cast to object in the null check?
32886
What is the difference between != and =! in Java?
35129
Why does String.valueOf(null) throw a NullPointerException?
114604
How to compare two java objects
90598
PHP considers null is equal to zero
33772
Is there any difference in equals and == for String variables?
114816
Is null reference possible?
152654
Comparing references in Java