How can I avoid unchecked cast warnings?

If we can’t eliminate the “unchecked cast” warning and we’re sure that the code provoking the warning is typesafe, we can suppress the warning using the SuppressWarnings(“unchecked”) annotation. When we use the @SuppressWarning(“unchecked”) annotation, we should always put it on the smallest scope possible.

What is an unchecked cast?

Unchecked cast means that you are (implicitly or explicitly) casting from a generic type to a nonqualified type or the other way around.

What is unchecked assignment in Java?

Unchecked assignment: ‘java.util.List’ to ‘java.util.List’ It means that you try to assign not type safe object to a type safe variable. If you are make sure that such assignment is type safe, you can disable the warning using @SuppressWarnings annotation, as in the following examples.

How do you handle an unchecked cast?

If an unchecked cast is unavoidable, a good idea is to tightly couple it with something that logically represents it’s type (like an enum or even instances of Class ), so you can glance at it and know it’s safe.

What is suppress warning unchecked?

An unchecked warning tells a programmer that a cast may cause a program to throw an exception somewhere else. Suppressing the warning with @SuppressWarnings(“unchecked”) tells the compiler that the programmer believes the code to be safe and won’t cause unexpected exceptions.

What is @SuppressWarnings Rawtypes?

If you choose to put @SuppressWarnings(“rawtypes”) at the method level, Eclipse will suppress all raw-types warnings inside that method. If we compile same code without @SuprressWarnings, using javac compiler it will show the following hint: $ javac RawType. java Note: RawType. java uses unchecked or unsafe operations.

What is @SuppressWarnings static access?

Here we get our first look at the @SuppressWarnings annotation. This annotation can be used to turn off compiler warnings – either all warnings or only certain ones. This video considers the warning a compiler gives you when you incorrectly call a static method.

What is reified in Kotlin?

To access the information about the type of class, we use a keyword called reified in Kotlin. In order to use the reified type, we need to use the inline function. If a function is marked as inline , then wherever the function is called, the compiler will paste the whole body of the function there.

What is @SuppressWarnings null?

null to suppress warnings relative to null analysis. restriction to suppress warnings relative to usage of discouraged or forbidden references.

Is there a way to avoid the unchecked cast?

In the HTTP Session world you can’t really avoid the cast, since the API is written that way (takes and returns only Object ). With a little bit of work you can easily avoid the unchecked cast, ‘though. This means that it will turn into a traditional cast giving a ClassCastException right there in the event of an error).

What’s the difference between a HashMap and a cast?

The problem is that a cast is a runtime check – but due to type erasure, at runtime there’s actually no difference between a HashMap and HashMap for any other Foo and Bar. Use @SuppressWarnings (“unchecked”) and hold your nose.

What is the problem with cast in Java?

In java class, the implementation looks like: In Eclipse, I see a warning that says: What went wrong? The problem is that a cast is a runtime check – but due to type erasure, at runtime there’s actually no difference between a HashMap and HashMap for any other Foo and Bar.

Can a unchecked cast turn into a CCE?

With a little bit of work you can easily avoid the unchecked cast, ‘though. This means that it will turn into a traditional cast giving a ClassCastException right there in the event of an error). An unchecked exception could turn into a CCE at any point later on instead of the point of the cast (that’s the reason why it’s a separate warning).