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Java program checks the class of an object obtained

In this example, we will learn to use the getClass() method, instanceof operator, and isInstance() method to determine the class of an object in Java.To understand this example, you should understand the followingJava programming

• Java Classes and Objects

• Topic:

Example1Java instanceof

: Use getClass() to check the class of an object1　class Test
//　first class
}
: Use getClass() to check the class of an object2　class Test
//　{
}
class Main {
　　public static void main(String[] args) {
　　　　//second class
　　　　create an object1　obj1　Test1= new Test
　　　　create an object2　obj2　Test2= new Test
　　　　//　();1gets the object obj
　　　　System.out.print("obj1is: ");
　　　　System.out.println(obj1.getClass());
　　　　//　();2gets the object obj
　　　　System.out.print("obj2is: ");
　　　　System.out.println(obj2.getClass());
　　}
}

Output Result

obj1is: class Test1
obj2is: class Test2

In the above example, we used the getClass() method of the Object class to get the class of the object obj1and obj2for the class name.

For more information, please visitJava Object getClass().

Example2: Use the instanceof operator to check the class of an object

class Test {
//　class
}
class Main {
　　public static void main(String[] args) {
　　　　//Create an object
　　　　Test obj = new Test();
　　　　//　Check if obj is an object of Test
　　　　if(obj instanceof Test) {
　　　　　　System.out.println("obj is an instance of the Test class");
　　　　}
　　　　else {
　　　　　　System.out.println("obj is not an instance of the Test class");
　　　　}
　　}
}

Output Result

obj is an instance of the Test class

In the above example, we use the instanceof operator to check if the object obj is an instance of Test.

Example3: Check the class of the object using isInstance()

class Test {
//　first class
}
class Main {
　　public static void main(String[] args) {
　　　　//Create an object
　　　　Test obj = new Test();
　　　　//Check if obj is an instance of Test1object
　　　　if (Test.class.isInstance(obj)) {
　　　　　　System.out.println("obj is an instance of the Test class");
　　　　}
　　　　else {
　　　　　　System.out.println("obj is not an instance of the Test class");
　　　　}
　　}
}

Output Result

obj is an instance of the Test class

In this example, we use the isInstance() method of the Class class to check if the object obj is an instance of the Test class.

The working principle of the isInstance() method is similar to the instanceof operator. However, it is best to use it at runtime.

Java Examples Comprehensive