how to declare an array list method in java code example

Example 1: how to define an arraylist in java

ArrayList<Integer> integerArray = new ArrayList<Integer>();
ArrayList<String> integerArray = new ArrayList<String>();
ArrayList<Double> integerArray = new ArrayList<Double>();
//... keep replacing what is inside the <> with the appropriate
//data type

Example 2: how to declare array of arraylist in java

List<List<Individual>> group = new ArrayList<List<Individual>>(4);