How to determine an object's class?

Use Object.getClass. It returns the runtime type of the object. Here's how to call it using your example:

class A {} class B extends A {} class C extends A {} class Main { public static void main(String args[]) { C c = new C(); Class clazz = c.getClass(); System.out.println(clazz); } } 

Output:

class C 

You can also compare two Class instances to see if two objects are the same type.

class A {} class B extends A {} class C extends A {} class Main { public static void main(String args[]) { B b = new B(); Class c1 = b.getClass(); C c = new C(); Class c2 = c.getClass(); System.out.println(c1 == c2); } } 

Multiple right answers were presented, but there are still more methods: Class.isAssignableFrom() and simply attempting to cast the object (which might throw a ClassCastException).

Possible ways summarized

Let's summarize the possible ways to test if an object obj is an instance of type C:

// Method #1 if (obj instanceof C) ; // Method #2 if (C.class.isInstance(obj)) ; // Method #3 if (C.class.isAssignableFrom(obj.getClass())) ; // Method #4 try { C c = (C) obj; // No exception: obj is of type C or IT MIGHT BE NULL! } catch (ClassCastException e) { } // Method #5 try { C c = C.class.cast(obj); // No exception: obj is of type C or IT MIGHT BE NULL! } catch (ClassCastException e) { } 

Differences in null handling

There is a difference in null handling though:

• In the first 2 methods expressions evaluate to false if obj is null (null is not instance of anything).
• The 3rd method would throw a NullPointerException obviously.
• The 4th and 5th methods on the contrary accept null because null can be cast to any type!

To remember: null is not an instance of any type but it can be cast to any type.

Notes

• Class.getName() should not be used to perform an "is-instance-of" test becase if the object is not of type C but a subclass of it, it may have a completely different name and package (therefore class names will obviously not match) but it is still of type C.
• For the same inheritance reason Class.isAssignableFrom() is not symmetric:
  obj.getClass().isAssignableFrom(C.class) would return false if the type of obj is a subclass of C.

You can use:

Object instance = new SomeClass(); instance.getClass().getName(); //will return the name (as String) (== "SomeClass") instance.getClass(); //will return the SomeClass' Class object 

HTH. But I think most of the time it is no good practice to use that for control flow or something similar...

Any use of any of the methods suggested is considered a code smell which is based in a bad OO design.

If your design is good, you should not find yourself needing to use getClass() or instanceof.

Any of the suggested methods will do, but just something to keep in mind, design-wise.

We can use reflection in this case

objectName.getClass().getName(); 

Example:-

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String name = request.getClass().getName(); }

In this case you will get name of the class which object pass to HttpServletRequest interface refference variable.

There is also an .isInstance method on the "Class" class. if you get an object's class via myBanana.getClass() you can see if your object myApple is an instance of the same class as myBanana via

myBanana.getClass().isInstance(myApple) 

checking with isinstance() would not be enough if you want to know in run time. use:

if(someObject.getClass().equals(C.class){ // do something } 

I Used Java 8 generics to get what is the object instance at runtime rather than having to use switch case

 public <T> void print(T data) { System.out.println(data.getClass().getName()+" => The data is " + data); } 

pass any type of data and the method will print the type of data you passed while calling it. eg

 String str = "Hello World"; int number = 10; double decimal = 10.0; float f = 10F; long l = 10L; List list = new ArrayList(); print(str); print(number); print(decimal); print(f); print(l); print(list); 

Following is the output

java.lang.String => The data is Hello World java.lang.Integer => The data is 10 java.lang.Double => The data is 10.0 java.lang.Float => The data is 10.0 java.lang.Long => The data is 10 java.util.ArrayList => The data is [] 

You can use getSimpleName().

Let's say we have a object: Dog d = new Dog(),

The we can use below statement to get the class name: Dog. E.g.:

d.getClass().getSimpleName(); // return String 'Dog'.

PS: d.getClass() will give you the full name of your object.

your_instance.getClass().getSimpleName() will gives type name for example: String, Integer, Double, Boolean...

class Superclass { // Superclass implementation } class Subclass extends Superclass { // Subclass implementation } public class Main { public static void main(String[] args) { Superclass obj = new Superclass(); // Check if the object is an instance of the superclass if (obj instanceof Superclass) { System.out.println("Object is an instance of Superclass"); } // Check if the object is an instance of the subclass if (obj instanceof Subclass) { System.out.println("Object is an instance of Subclass"); } else { System.out.println("Object is not an instance of Subclass"); } } } 

I use the blow function in my GeneralUtils class, check it may be useful

 public String getFieldType(Object o) { if (o == null) { return "Unable to identify the class name"; } return o.getClass().getName(); } 

use instanceof operator to find weather a object is of particular class or not.

booleanValue = (object instanceof class) 

JDK 14 extends the instanceof operator: you can specify a binding variable; if the result of the instanceof operator is true, then the object being tested is assigned to the binding variable.

please visit official Java documentation for more reference.

Sample program to illustrate usage of instanceof operator :

import java.util.*; class Foo{ @Override public String toString(){ return "Bar"; } } class Bar{ public Object reference; @Override public String toString(){ return "Foo"; } } public class InstanceofUsage{ public static void main(final String ... $){ final List<Object> list = new ArrayList<>(); var out = System.out; list.add(new String("Foo Loves Bar")); list.add(33.3); list.add(404_404); list.add(new Foo()); list.add(new Bar()); for(final var o : list){ if(o instanceof Bar b && b.reference == null){ out.println("Bar : Null"); } if(o instanceof String s){ out.println("String : "+s); } if(o instanceof Foo f){ out.println("Foo : "+f); } } } } 

output:

$ javac InstanceofUsage.java && java InstanceofUsage String : Foo Loves Bar Foo : Bar Bar : Null