• Home
• io.github.erroraway
• sonar-erroraway-sonar-plugin
• 2.2.0
• source code
• IsInstanceOfClass.md

×

Project download

Many resources are needed to download a project. Please understand that we have to compensate our server costs. Thank you in advance.
Project price only 1 $

You can buy this project and download/modify it how often you want.

errorprone.bugpattern.IsInstanceOfClass.md Maven / Gradle / Ivy

Passing an argument of type `Class` to `Class#instanceOf(Class)` is usually a
mistake.

Calling `clazz.instanceOf(obj)` for some `clazz` with type `Class` is
equivalent to `obj instanceof T`. The `instanceOf` method exists for cases where
the type `T` is not known statically.

When a class literal is passed as the argument of `instanceOf`, the result will
only be true if the class literal on left hand side is equal to `Class.class`.

For example, the following code returns true if and only if the type `A` is
equal to `Class` (i.e. lhs is equal to `Class.class`).

```java
 boolean f(Class lhs, Class rhs) {
  return lhs.instanceOf(rhs); // equivalent to 'lhs == Class.class'
}
```

To test if the type represented by a class literal is a subtype of the type
represented by some other class literal, `isAssignableFrom` should be used
instead:

```java
 boolean f(Class lhs, Class rhs) {
  return lhs.isAssignableFrom(rhs); // equivalent to 'B instanceof A'
}
```