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javacollections

Java ArrayList and HashMap on-the-fly


Can someone please provide an example of creating a Java ArrayList and HashMap on the fly? So instead of doing an add() or put(), actually supplying the seed data for the array/hash at the class instantiation?

To provide an example, something similar to PHP for instance:

$array = array (3, 1, 2);
$assoc_array = array( 'key' => 'value' );

Solution

  • List<String> list = new ArrayList<String>() {
     {
        add("value1");
        add("value2");
     }
    };
    
    Map<String,String> map = new HashMap<String,String>() {
     {
        put("key1", "value1");
        put("key2", "value2");
     }
    };