The instanceof
keyword in Java is used to test whether an object is an instance of a particular class or interface. It is often used in conditional statements to determine the type of an object before performing certain operations.
Following is the basic syntax:
if (object instanceof ClassName) {
// Code to execute if the object is an instance of ClassName
} else {
// Code to execute if the object is not an instance of ClassName
}
Example:
public class InstanceOfDemo {
public static void main(String[] args) {
Object obj = "Hello, Java!";
if (obj instanceof String) {
System.out.println("The object is a String.");
String str = (String) obj; // We can safely cast obj to String here
System.out.println("Length of the string: " + str.length());
} else {
System.out.println("The object is not a String.");
}
}
}
In this example, the instanceof
keyword is used to check if the object obj
is an instance of the String
class. If true, it then safely casts the object to a String
and performs operations specific to that type. If false, it handles the case where the object is not a String
.