Why do I get this error? Example As a real world comparison, what just happened is this conversation: Hey, how much gas is left in the tank of the car? What are you talking about, we don’t have a car. That is exactly what is happening in your program. You wanted to call a function … Read more
There are basically 4 techniques for this task, all of them standard SQL. NOT EXISTS Often fastest in Postgres. SELECT ip FROM login_log l WHERE NOT EXISTS ( SELECT — SELECT list mostly irrelevant; can just be empty in Postgres FROM ip_location WHERE ip = l.ip ); Also consider: What is easier to read in … Read more
The field annotated @Autowired is null because Spring doesn’t know about the copy of MileageFeeCalculator that you created with new and didn’t know to autowire it. The Spring Inversion of Control (IoC) container has three main logical components: a registry (called the ApplicationContext) of components (beans) that are available to be used by the application, … Read more
What is the cause? Bottom Line You are trying to use something that is null (or Nothing in VB.NET). This means you either set it to null, or you never set it to anything at all. Like anything else, null gets passed around. If it is null in method “A”, it could be that method … Read more
Is there a standard function to check for null, undefined, or blank variables in JavaScript?
How can I check for an empty/undefined/null string in JavaScript?
Avoiding NullPointerException in Java
Before the loop pointer pArray points to the first character of array charArray due to its initialization. char* pArray = charArray; So inside the loop at the first iteration *pArray yields reference to the first character of the array. Thus the referenced character is assigned by character literal ‘\0’. *pArray = ‘\0’; Then the pointer … Read more
You have an upper case “I” in If (…. Change it to lower case: if (…. JavaScript is case-sensitive.