Automatically call specific method at other method invocation~ish?

Question

I have a class which basically acts as a wrapper around a List. It contains a List object and some methods that do something with that list.
Now, in order to prevent exceptions, I've made a basic method that just checks if the List field is null and, if so, it will create a new ArrayList and chuck it in that field.
Right now, I just have a call to that particular method in each other method that performs an operation on the list, like so:
public class SomeClass<T> {
   private List<T> list;
   private void checkList() {
     if ( list == null) {
       list = new ArrayList<T>();
  public int method() {
    checkList();
    return list.doSomething();
  }Is there a way, prefferably a native Java way, to automatically have the checkList() method called before each and any method invocation? As in, whenever a method is called in the SomeClass, Java / the JVM automatically calls the checkList method?
}

Answer 1

Yop wrote:
I have a class which basically acts as a wrapper around a List. It contains a List object and some methods that do something with that list.
Now, in order to prevent exceptions, I've made a basic method that just checks if the List field is null and, if so, it will create a new ArrayList and chuck it in that field.
Right now, I just have a call to that particular method in each other method that performs an operation on the list, like so:
public class SomeClass<T> {
private List<T> list;
private void checkList() {
if ( list == null) {
list = new ArrayList<T>();
public int method() {
checkList();
return list.doSomething();
}Is there a way, prefferably a native Java way, to automatically have the checkList() method called before each and any method invocation? As in, whenever a method is called in the SomeClass, Java / the JVM automatically calls the checkList method?
}Why not return the List<T> in the check() method? Like this:
List<T> check() {
   if (list == null) list= new ArrayList<T>();
   return list;
void otherMethod(T t) {
   check().add(t);
}Instead of using variable 'list' directly, use the 'check()' method.
kind regards,
Jos