Double Brace Initialization in Java! Java Initialization technique

List<String> countries = new ArrayList<String>() {{     add("India");     add("Switzerland");     add("Italy");     add("France");     add("Germany"); }};

Well, the double brace ( {{ .. }} ) initialization in Java works this way. The first brace creates a new AnonymousInnerClass, the second declares an instance initializer block that is run when the anonymous inner class is instantiated.

This type of initializer block is formally called an “instance initializer”, because it is declared withing the instance scope of the class — “static initializers” are a related concept where the keyword static is placed before the brace that starts the block, and which is executed at the class level as soon as the classloader completes loading the class . The initializer block can use any methods, fields and final variables available in the containing scope, but one has to be wary of the fact that initializers are run before constructors.
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