eventIn defines a way that the VRML file can access the Java program. Typically the eventIn parameter tells the VRML file, "Hey, here's a method in my Java program that you can call." It allows the VRML file to call methods in the Java program.
The syntax is
eventIn [type] [name]The type field tells the Java program what type of argument the VRML file will pass it. See below for details.