How to convert String type to Class type in java

Question

I want to print all the class names in a package and also to print the corresponding attributes and their data types in each package.

In one code, I am able to get the classnames in the form of string. In another code I am able to get the attributes and their data types using Classname.class.getAttribute();

However I want to merge the two codes. Since in the first code I got the classnames in the form of string , I can't use Classname.class.getAttribute() since here Classname will be of type String.

So I want a method which will convert the "Classname" from String type to Class type.

I tried Class.forName() but it didn't work.

If Class.forName() didn't work, its very likely that a) the class name is not right b) you got an error message but didn't know what it meant so you ignored it. ;) — Peter Lawrey
– Peter Lawrey, Commented Sep 5, 2012 at 17:40
Post your error message! and post the code where you tried using Class.forName() — Colin D
– Colin D, Commented Sep 5, 2012 at 17:44

Piyush Mattoo · Accepted Answer · 2012-09-05 17:42:13Z

27

Class<?> classType = Class.forName(className);

Make sure className is fully qualified class name like com.package.class Also, please share your error message that you see.

answered Sep 5, 2012 at 17:42

Piyush Mattoo

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1 Comment

Bipin Wanchoo Over a year ago

Yes, the className was not fully qualified. Upon giving the fully qualified name, it worked :) Thanks :)

heretolearn · Accepted Answer · 2012-09-05 18:33:45Z

1

If the fully-qualified name of a class is available, it is possible to get the corresponding Class using the static method Class.forName().

Eg:

Class c = Class.forName("com.duke.MyLocaleServiceProvider");

Note: Make sure the parameter you provide for the function is fully qualified class name like com.package.class

Check here for any reference.

EDIT:

You could also try using loadClass() method.

Eg:

 ClassLoader cl;
 Class c = cl.loadClass(name);

It is invoked by the Java virtual machine to resolve class references.

Syntax:

public Class<?> loadClass(String name)
                   throws ClassNotFoundException

For details on ClassLoader check here

Here is an implementation of ClassLoader.

edited Sep 5, 2012 at 18:33

answered Sep 5, 2012 at 18:01

heretolearn

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Comments

Sandun Madola · Accepted Answer · 2017-07-24 11:59:17Z

1

Please try as following.

String str = "RequiredClassName";    
Class <?> Cref = Class .forName("PackageNaem."+str );

edited Jul 24, 2017 at 11:59

Sandun Madola

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answered Jul 24, 2017 at 11:06

Pranay

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