CODEWITHSUNDEEP
javatomcatclassloader
Jeff Storey
Jeff Storey

Reputation: 57192

Dynamic class loading in Spring/Tomcat

I am currently using 

String myClass; // dynamically determined class name
Class.forName(myClass).newInstance()

to dynamically load objects in a spring app deployed to a tomcat server.

I've been reading (http://blog.bjhargrave.com/2007/09/classforname-caches-defined-class-in.html) that it a preferred approach to dynamically loading classes is using the ClassLoader.loadClass, such as 

ClassLoader.getSystemClassLoader().loadClass(myClass).newInstance()

In the second example, using loadClass, I am getting an error that the class is not found. I suspect this is because I'm running within Tomcat the system class loader is not the class loader I actually want to be using.

When in a Tomcat app, which class loader should I be using if I want to use the loadClass mechanism?

Upvotes: 3

Views: 6411

Answers (2)

Avinash Singh
Avinash Singh

Reputation: 3777

You can use getClassLoader().loadClass(myClass).newInstance() ,

It will look for the class in current classloader and will go to the parent classloader if not found.

myClass should be the fully qualified name like java.lang.String

Upvotes: 1

Zagrev
Zagrev

Reputation: 2020

Typically, you want to use the classloader that loaded your currently executing code. That is, you just want to call getClass().getClassLoader().loadClass(...). That said, there are times when you need to use a different class loader. When that is necessary requires hours and hours of training. So, you should always use the loader that loaded the currently executing code.

Upvotes: 2

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