Can anyone replicate this?

diordna,
I think you might be confusing syntax from Processing's continuous mode and Java mode.

In continuous mode, classes are inner classes-the class declaration happens within another class.

In Java mode, you'd stick you're MyType class in another tab and name it MyType.java.

Here's your example in continuous mode (notice I got rid of the Java mode syntax):

Code:

void setup(){
  MyType t = new MyType();
}

class MyType{
  MyType(){
  }
}
 

Here it is in Java mode:
Code:

public class Test extends PApplet {
  void setup(){
    MyType t = new MyType();
  }
}
 

You need another tab, named "MyType.java", which needs to include (at least):
Code:

public class MyType{
  public MyType(){
  } 
}
 

Although, you can also treat MyType as an inner class in Java mode:

Code:

// Java mode with inner class
public class Test extends PApplet {
  void setup(){
    MyType t = new MyType();
  }

  //inner class
  class MyType{
    MyType(){
    }
  } 
}


 

see the reference for "sketchbook" and "tabs (multiple files)" for more info:
http://processing.org/reference/environment/index.html