CODEWITHSUNDEEP
javaclassload
Pacerier
Pacerier

Reputation: 89613

java: Class.Load?

I'm fairly confused about the Class.forName in java. how do we explain what Class.forName is from a C# perspective?

use case: java.lang.Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");

Upvotes: 0

Views: 476

Answers (2)

sbridges
sbridges

Reputation: 25140

Class.forName returns an instance of a Class object. Class is equivalent to the c# class object.

Class.forName forces classes to load, if they have not already been loaded. As part of the class loading process is invoking any static blocks defined in the class. A static block looks like,

class Foo {
    static {
         System.out.println("loaded Foo");
    }
}

//running this will print "loaded Foo"
Class.forName("Foo");

Static blocks are invoked only once, the first time a class is loaded, so repeatedly calling Class.forName("Foo") will only cause "loaded Foo" to be printed once. Creating a new instance of Foo will also cause the class to be loaded, if it has not already been loaded.

Generally, JDBC drivers will register themselves by calling DriverManager.registerDriver() in a static block, which is why calling Class.forName() loads the driver.

Upvotes: 3

Lak Ranasinghe
Lak Ranasinghe

Reputation: 240

You can use java.lang.Class.forName, when you want to instantiate an object in Java by simply giving objects name as a String.

Its similar to using Activator.CreateInstance(objectType) in c#.

For more info, read http://java.sun.com/developer/technicalArticles/ALT/Reflection/ and http://msdn.microsoft.com/en-us/library/d49ss92b(v=VS.71).aspx

Upvotes: 1

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