HashMap.containsKey(s.charAt(i)) evaluates to true but map.get(s.charAt(i)) results in Null Pointer Exception?
49
What is a NullPointerException, and how do I fix it?
99777
Bug in List.contains for Id data type?
62369
Iterate through a HashMap
43929
What happens if you call erase() on a map element while iterating from begin to end?
148412
How can I use hasNextInt() to catch an exception? I need Int but if input is character, that is bad
33995
CharSequence VS String in Java?
108024
What are the differences between a HashMap and a Hashtable in Java?
5640
How to check a string against null in java?
35129
Why does String.valueOf(null) throw a NullPointerException?
32239
contains method of String is not working properly
132458
this class is not key value coding-compliant for the key givenName
113850
How do I convert a String to an InputStream in Java?
19123
"unmappable character for encoding" warning in Java
106080
Is the order guaranteed for the return of keys and values from a LinkedHashMap object?
142913
How do you get the "object reference" of an object in java when toString() and hashCode() have been overridden?
38263
How can I combine two HashMap objects containing the same types?
64704
Behaviour of LinkedHashMap's keySet() and values() methods