Attempt to invoke virtual method 'java.lang.String java.lang.String.toUpperCase()' on a null object reference
49
What is a NullPointerException, and how do I fix it?
53319
ArgumentException or ArgumentNullException for string parameters?
54143
Why is the default value of the string type null instead of an empty string?
128142
java.lang.NullPointerException at org.apache.jsp.foo_jsp._jspInit(foo_jsp.java:22)
96843
What will happen when I call a member function on a NULL object pointer?
152733
How to simplify a null-safe compareTo() implementation?
103224
Why does 10..toString() work, but 10.toString() does not?
13711
java.lang.NullPointerException at org.glassfish.hk2.classmodel.reflect.impl.TypesImpl.getType
143697
Method must have signature "String method() ...[etc]..." but has signature "void method()"
93104
What is a NumberFormatException and how can I fix it?
32065
Attempt to de-reference a null object: Trigger
33103
How come invoking a (static) method on a null reference doesn't throw NullPointerException?
42958
Method Overloading for null argument
78586
Why doesn't "System.out.println" work in Android?
156920
Java.lang.verifyerror how do I fix or even find out the root cause?
146379
Java method dispatch with null argument
115607
Why doesn't String switch statement support a null case?