I am wondering how the parameter of ... works in Java. For example:

public void method1(boolean... arguments)
{
  //...     
}

Is this like an array? How I should access the parameter?

Its called Variable arguments or in short var-args, introduced in Java 1.5. The advantage is you can pass any number of arguments while calling the method.

For instance:

public void method1(boolean... arguments) throws Exception {
    for(boolean b: arguments){ // iterate over the var-args to get the arguments.
       System.out.println(b);
    }
 }

The above method can accept all the below method calls.

method1(true);
method1(true, false);
method1(true, false, false);