Print the type name of object held by variable

Question

In Java, is it possible to print the type of value held by variable?

public static void printVariableType(Object theVariable){
    //for example, if passed argument is "abc", print "String" to the console.
}

One approach to this problem would be to use an if-statement for each variable type, but that would seem redundant, so I'm wondering if there's a better way to do this:

if(theVariable instanceof String){
    System.out.println("String");
}
if(theVariable instanceof Integer){
    System.out.println("Integer");
}
// this seems redundant and verbose. Is there a more efficient solution (e. g., using reflection?).

This question has a deceptively similar title to this one, but appears to be mostly irrelevant: stackoverflow.com/questions/6614066/… — Anderson Green
– Anderson Green, Commented Apr 2, 2013 at 17:32

Pshemo · Accepted Answer · 2022-08-27 11:14:31Z

39

I am assuming that in case of Animal myPet = new Cat(); you want to get Cat not Animal nor myPet.

To get only name without package part use

String name = theVariable.getClass().getSimpleName(); //to get Cat

otherwise

String name = theVariable.getClass().getName(); //to get full.package.name.of.Cat

edited Aug 27, 2022 at 11:14

answered Apr 2, 2013 at 17:36

Pshemo

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JB Nizet · Accepted Answer · 2013-04-02 17:32:22Z

17

System.out.println(theVariable.getClass());

Read the javadoc.

answered Apr 2, 2013 at 17:32

JB Nizet

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Femaref · Accepted Answer · 2013-04-02 17:33:49Z

6

You can use the ".getClass()" method.

System.out.println(variable.getClass());

edited Apr 2, 2013 at 17:33

Femaref

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answered Apr 2, 2013 at 17:33

Marcelo Tataje

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Achintya Jha · Accepted Answer · 2013-04-02 17:42:56Z

6

variable.getClass().getName();

Object#getClass()

Returns the runtime class of this Object. The returned Class object is the object that is locked by static synchronized methods of the represented class.

edited Apr 2, 2013 at 17:42

answered Apr 2, 2013 at 17:34

Achintya Jha

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Jakub Zaverka · Accepted Answer · 2013-04-02 17:32:51Z

4

public static void printVariableType(Object theVariable){
    System.out.println(theVariable.getClass())
}

answered Apr 2, 2013 at 17:32

Jakub Zaverka

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MCWhitaker · Accepted Answer · 2013-04-02 17:34:03Z

4

You can read in the class, and then get it's name.

Class objClass = obj.getClass();  
System.out.println("Type: " + objClass.getName());

answered Apr 2, 2013 at 17:34

MCWhitaker

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Ashish Mishra · Accepted Answer · 2021-05-02 02:59:13Z

0

public static void printVariableType(Object theVariable){
    System.out.println(theVariable);        
    System.out.println(theVariable.getClass()); 
    System.out.println(theVariable.getClass().getName());}



   ex- printVariableType("Stackoverflow");
    o/p: class java.lang.String // var.getClass()
         java.lang.String       // var.getClass().getName()

edited May 2, 2021 at 2:59

answered May 1, 2021 at 13:17

Ashish Mishra

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