A set of Java knowledge

of java.util.ArrayList Import; 

/ * 
length of the array is not altered 
but the length can be freely set ArrayList changed 

for ArrayList, there is a angle bracket <E> Representative generic 
generic: which is mounted in the collection All the elements are all unified type of 
generic types can not only be a reference to the basic type 


* / 
public class Arraylist { 
    public static void main (String [] args) { 
        // create an ArrayList collection, name of the collection is a list inside string string is filled with all types of data 

        ArrayList <string> list = new ArrayList <> (); // Create a set of string type is stored 
        instead of the address value is set ArrayList // for direct printing content but obtained If the content is empty is obtained empty brackets 
        System.out.println (List); // [] 

        // add to the collection of data which need to use some of the add method 
        list.add ( "Zhao Liying"); 
        List.add ( "now Lee"); 
        //list.add(100);// which can add a set of string type that is set by the nature of the decision and

If you want to set basic types of data stored in the ArrayList must use substantially corresponds to the type "packaging" 

        System.out.println(list);

    }
}