You can use reflection. Reflection is tricky and doesn't perform well, so you should think about whether or not this is how you really want to proceed.
However, the code would look like
for (int i = 1 ; i <= 4; i++) {
Method method = this.getClass().getDeclaredMethod("method"+i);
method.invoke(this);
}
assuming the methods are not static and are defined in the current class.
