You could change the method return type to return java. lang. Integer and then you can return null, and existing code that returns int will get autoboxed. Nulls are assigned only to reference types, it means the reference doesn’t point to anything.

The method signature clearly states that it can return a null reference. This way, callers know for sure that they need to implement error handling just by looking at the method signature.

When null is returned from a method, it usually means that the method was not able to create a meaningful result. For example the method, that reads data from database was not able to find the specified object or some error occurred during the method run.

In Java programming, null can be assigned to any variable of a reference type (that is, a non-primitive type) to indicate that the variable does not refer to any object or array. Object . That means that null cannot be used in place of a reference to a Java object like an instance of java. lang.

Returning null Creates More Work An ideal function, like an assistant cook, will encapsulate work and produce something useful. A function that returns a null reference achieves neither goal. Returning null is like throwing a time bomb into the software. Other code must a guard against null with if and else statements.

Answer: Some of the best practices to avoid NullPointerException are:

1. Use equals() and equalsIgnoreCase() method with String literal instead of using it on the unknown object that can be null.
2. Use valueOf() instead of toString() ; and both return the same result.
3. Use Java annotation @NotNull and @Nullable.

Returning null is usually the best idea if you intend to indicate that no data is available. An empty object implies data has been returned, whereas returning null clearly indicates that nothing has been returned.

Null or NULL is a special marker used in Structured Query Language to indicate that a data value does not exist in the database. SQL null is a state, not a value. This usage is quite different from most programming languages, where null value of a reference means it is not pointing to any object.

Another popular and faster way to check if String is empty or not is by checking it’s length, e.g. if String.length() = 0 then String is empty, but this is also not null safe. Third common way of checking emptiness of String in Java is comparing it with empty String literal e.g.

A null indicates that a variable doesn’t point to any object and holds no value. You can use a basic ‘if’ statement to check a null in a piece of code. Null is commonly used to denote or verify the non-existence of something. Within that context, it can be used as a condition to start or stop other processes within the code.

return is a reserved keyword in Java i.e, we can’t use it as an identifier. It is used to exit from a method, with or without a value. return can be used with methods in two ways: Methods returning a value : For methods that define a return type, return statement must be immediately followed by return value.

A method is a unit of code that you call in a Java program. A method can support arguments and usually returns a value. To create a method in Java, follow these four steps. Open your text editor and create a new file. The method you have coded is named computeAreaOfRectangle.